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Whitcher TJ, Fauzi AD, Diao C, Chi X, Syahroni A, Asmara TC, Breese MBH, Castro Neto AH, Wee ATS, Majidi MA, Rusydi A. Reply to: Reassessing the existence of soft X-ray correlated plasmons. Nat Commun 2023; 14:6754. [PMID: 37875490 PMCID: PMC10597986 DOI: 10.1038/s41467-023-40652-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/01/2023] [Indexed: 10/26/2023] Open
Affiliation(s)
- T J Whitcher
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore.
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore.
- Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore, 117546, Singapore.
| | - A D Fauzi
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - C Diao
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - X Chi
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - A Syahroni
- Department of Physics, University of Indonesia, Depok, 16424, Indonesia
| | - T C Asmara
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
| | - M B H Breese
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - A H Castro Neto
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore
| | - A T S Wee
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore
| | - M A Majidi
- Department of Physics, University of Indonesia, Depok, 16424, Indonesia
| | - A Rusydi
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore.
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore.
- Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore, 117546, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore.
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Yu XJ, Chi X, Smulders T, Wee ATS, Rusydi A, Sanchez del Rio M, Breese MBH. Beamline simulations using monochromators with high d-spacing crystals. J Synchrotron Radiat 2022; 29:1157-1166. [PMID: 36073874 PMCID: PMC9455208 DOI: 10.1107/s160057752200707x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Monochromators for synchrotron radiation beamlines typically use perfect crystals for the hard X-ray regime and gratings for soft X-rays. There is an intermediate range, typically 1-3 keV (tender X-rays), which common perfect crystals have difficulties covering and gratings have low efficiency, although some less common crystals with high d-spacing could be suitable. To evaluate the suitability of these crystals for a particular beamline, it is useful to evaluate the crystals' performance using tools such as ray-tracing. However, simulations for double-crystal monochromators are only available for the most used crystals such as Si, Ge or diamond. Here, an upgrade of the SHADOW ray-tracing code and complementary tools in the OASYS suite are presented to simulate high d-spacing crystals with arbitrary, and sometimes complex, structures such as beryl, YB66, muscovite, etc. Isotropic and anisotropic temperature factors are also considered. The YB66 crystal with 1936 atomic sites in the unit cell is simulated, and its applicability for tender X-ray monochromators is discussed in the context of new low-emittance storage rings.
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Affiliation(s)
- X. J. Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - X. Chi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
| | - T. Smulders
- Department of Engineering Physics, Fonty University of Applied Sciences, 5615DB Eindhoven, The Netherlands
| | - A. T. S. Wee
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore
| | - A. Rusydi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore
| | | | - M. B. H. Breese
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
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Ong BL, Jayaraman K, Diao C, Whitcher TJ, Jain A, Hung H, Breese MBH, Tok ES, Rusydi A. Anomalous Ferromagnetism of quasiparticle doped holes in cuprate heterostructures revealed using resonant soft X-ray magnetic scattering. Nat Commun 2022; 13:4639. [PMID: 35941141 PMCID: PMC9360448 DOI: 10.1038/s41467-022-31885-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 07/04/2022] [Indexed: 11/09/2022] Open
Abstract
We report strong ferromagnetism of quasiparticle doped holes both within the ab-plane and along the c-axis of Cu-O planes in low-dimensional Au/d-La1.8Ba0.2CuO4/LaAlO3(001) heterostructures (d = 4, 8 and 12 unit-cells) using resonant soft X-ray and magnetic scattering together with X-ray magnetic circular dichroism. Interestingly, ferromagnetism is stronger at a hole doped peak and at an upper Hubbard band of O with spin-polarization degree as high as 40%, revealing strong ferromagnetism of Mottness. For in-ab-plane spin-polarizations, the spin of doped holes in O2p-Cu3d-O2p is a triplet state yielding strong ferromagnetism. For out-of-ab-plane spin-polarization, while the spins of doped holes in both O2p-O2p and Cu3d-Cu3d are triplet states, the spin of doped holes in Cu3d-O2p is a singlet state yielding ferrimagnetism. A ferromagnetic-(002) Bragg-peak of the doped holes is observed and enhanced as a function of d revealing strong ferromagnetism coupling between Cu-O layers along the c-axis.
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Affiliation(s)
- B L Ong
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - K Jayaraman
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - C Diao
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - T J Whitcher
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - A Jain
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - H Hung
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - M B H Breese
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore.,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - E S Tok
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore
| | - A Rusydi
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117551, Singapore. .,Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore. .,Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117546, Singapore. .,NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore.
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4
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Whitcher TJ, Fauzi AD, Caozheng D, Chi X, Syahroni A, Asmara TC, Breese MBH, Neto AHC, Wee ATS, Majidi MA, Rusydi A. Unravelling strong electronic interlayer and intralayer correlations in a transition metal dichalcogenide. Nat Commun 2021; 12:6980. [PMID: 34848717 PMCID: PMC8632915 DOI: 10.1038/s41467-021-27182-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 10/27/2021] [Indexed: 11/23/2022] Open
Abstract
Electronic correlations play important roles in driving exotic phenomena in condensed matter physics. They determine low-energy properties through high-energy bands well-beyond optics. Great effort has been made to understand low-energy excitations such as low-energy excitons in transition metal dichalcogenides (TMDCs), however their high-energy bands and interlayer correlation remain mysteries. Herewith, by measuring temperature- and polarization-dependent complex dielectric and loss functions of bulk molybdenum disulphide from near-infrared to soft X-ray, supported with theoretical calculations, we discover unconventional soft X-ray correlated-plasmons with low-loss, and electronic transitions that reduce dimensionality and increase correlations, accompanied with significantly modified low-energy excitons. At room temperature, interlayer electronic correlations, together with the intralayer correlations in the c-axis, are surprisingly strong, yielding a three-dimensional-like system. Upon cooling, wide-range spectral-weight transfer occurs across a few tens of eV and in-plane p-d hybridizations become enhanced, revealing strong Coulomb correlations and electronic anisotropy, yielding a two-dimensional-like system. Our result shows the importance of strong electronic, interlayer and intralayer correlations in determining electronic structure and opens up applications of utilizing TMDCs on plasmonic nanolithrography.
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Affiliation(s)
- T J Whitcher
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore.
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore.
- Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore, 117546, Singapore.
| | - Angga Dito Fauzi
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - D Caozheng
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - X Chi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore, 117546, Singapore
| | - A Syahroni
- Department of Physics, University of Indonesia, Depok, 16424, Indonesia
| | - T C Asmara
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
| | - M B H Breese
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
| | - A H Castro Neto
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
- NUSSNI-NanoCore, National University of Singapore, Singapore, 117576, Singapore
| | - A T S Wee
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore
- NUSSNI-NanoCore, National University of Singapore, Singapore, 117576, Singapore
| | - M Aziz Majidi
- Department of Physics, University of Indonesia, Depok, 16424, Indonesia
| | - A Rusydi
- Advanced Research Initiative for Correlated-Electron Systems (ARiCES), Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore, 117576, Singapore.
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, Singapore.
- Centre for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore, 117546, Singapore.
- NUSSNI-NanoCore, National University of Singapore, Singapore, 117576, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, Singapore, 117456, Singapore.
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5
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de Marcos LR, Leong OB, Asmara TC, Heussler SP, Breese MBH, Rusydi A. Nanoscale dielectric grating polarizers tuned to 4.43 eV for ultraviolet polarimetry. Opt Express 2020; 28:12936-12950. [PMID: 32403779 DOI: 10.1364/oe.382839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 01/31/2020] [Indexed: 06/11/2023]
Abstract
Transmissive dielectric wire grid polarizers tuned to 4.43 eV (Mg II line, 280 nm), an important diagnostic line for solar physics, are presented in this communication. The polarizers are based on TiO2 gratings and designed with a period of ∼140 nm (7143 lines/mm), 40 nm line width (duty cycle of 0.286), and 100 nm line height. Several gratings are fabricated through electron beam lithography combined with reactive ion etching, whereby two parameters in the nanofabrication process are explored: e-beam dosage on the photoresist and TiO2 etching time. Polarization of samples is optically characterized using a spectroscopic ellipsometer in transmission mode, achieving the best result with an extinction ratio of ∼109 and a transmittance of 16.4% at the target energy of 4.43 eV. The shape of the gratings is characterized through atomic force microscopy (AFM) and scanning electron microscopy (SEM); the measured AFM profiles are distorted by the tip geometry, hence a simple deconvolution procedure is implemented to retrieve the real profile. By analysing the AFM and SEM profiles, we find that the real shapes of the different gratings are close to the design, but with a larger duty cycle than the intended value. With the real grating geometry, an improved model of the best sample was built with a finite-difference time-domain (FDTD) method that matches the result obtained through optical characterization.
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Yu XJ, Diao CZ, Venkatesan T, Breese MBH, Rusydi A. A soft x-ray-ultraviolet (SUV) beamline and diffractometer for resonant elastic scattering and ultraviolet-vacuum ultraviolet reflectance at the Singapore synchrotron light source. Rev Sci Instrum 2018; 89:113113. [PMID: 30501296 DOI: 10.1063/1.5043341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/23/2018] [Indexed: 05/22/2023]
Abstract
A new beamline and a six-circle UHV diffractometer have been constructed at the Singapore Synchrotron Light Source with a broad energy coverage from 3.5 to 1500 eV. The beamline is optimized for ultraviolet-vacuum-ultraviolet optical reflectivity and resonant soft X-ray scattering with medium energy resolution over a broad energy range, achieved by using a self-focusing monochromator consisting of a plane mirror and three variable line spacing gratings. The unique character of the diffractometer comprises 4-circles in the vertical plane and 2-circles in the horizontal plane. Thirteen motions are available inside the UHV chamber with a base pressure of 1 × 10-9 mbar. Two sample holders working independently over a temperature range of 37 K-400 K are controlled by a closed-cycle cryostat, while the bottom holder inside a high field compact pulsed magnet is available for measurements requiring a magnetic field.
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Affiliation(s)
- X J Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - C Z Diao
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - T Venkatesan
- NUSSNI-NanoCore, National University of Singapore, Singapore 117576, Singapore
| | - M B H Breese
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - A Rusydi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
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Banas A, Banas K, Kalaiselvi SMP, Pawlicki B, Kwiatek WM, Breese MBH. Is it possible to find presence of lactose in pharmaceuticals? - Preliminary studies by ATR-FTIR spectroscopy and chemometrics. Spectrochim Acta A Mol Biomol Spectrosc 2017; 171:280-286. [PMID: 27541800 DOI: 10.1016/j.saa.2016.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 07/31/2016] [Accepted: 08/03/2016] [Indexed: 06/06/2023]
Abstract
Lactose and saccharose have the same molecular formula; however, the arrangement of their atoms is different. A major difference between lactose and saccharose with regard to digestion and processing is that it is not uncommon for individuals to be lactose intolerant (around two thirds of the population has a limited ability to digest lactose after infancy), but it is rather unlikely to be saccharose intolerant. The pharmaceutical industry uses lactose and saccharose as inactive ingredients of drugs to help form tablets because of their excellent compressibility properties. Some patients with severe lactose intolerance may experience symptoms of many allergic reactions after taking medicine that contains this substance. People who are specifically "allergic" to lactose (not just lactose intolerant) should not use tablets containing this ingredient. Fourier Transform Infrared (FTIR) spectroscopy has a unique chemical fingerprinting capability and plays a significant important role in the identification and characterization of analyzed samples and hence has been widely used in pharmaceutical science. However, a typical FTIR spectrum collected from tablets contains a myriad of valuable information hidden in a family of tiny peaks. Powerful multivariate spectral data processing can transform FTIR spectroscopy into an ideal tool for high volume, rapid screening and characterization of even minor tablet components. In this paper a method for distinction between FTIR spectra collected for tablets with or without lactose is presented. The results seem to indicate that the success of identifying one component in FTIR spectra collected for pharmaceutical composition (that is tablet) is largely dependent on the choice of the chemometric technique applied.
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Affiliation(s)
- A Banas
- Singapore Synchrotron Light Source, 5 Research Link, 117603 Singapore, Singapore.
| | - K Banas
- Singapore Synchrotron Light Source, 5 Research Link, 117603 Singapore, Singapore
| | - S M P Kalaiselvi
- Singapore Synchrotron Light Source, 5 Research Link, 117603 Singapore, Singapore
| | - B Pawlicki
- Gabriel Narutowicz Hospital, Pradnicka 37, 31-202 Krakow, Poland
| | - W M Kwiatek
- Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Krakow, Poland
| | - M B H Breese
- Singapore Synchrotron Light Source, 5 Research Link, 117603 Singapore, Singapore
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8
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Liang HD, Vanga SK, Wu JF, Xiong BQ, Yang CY, Bettiol AA, Breese MBH. Fabrication of 3D photonic components on bulk crystalline silicon. Opt Express 2015; 23:121-129. [PMID: 25835659 DOI: 10.1364/oe.23.000121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have fabricated three dimensional photonic components such as waveguides and beam splitters from crystalline silicon using a process based on one or more ion irradiation steps with different energies and fluences, followed by electrochemical anodization and thermal annealing. We first demonstrate the fabrication of multilevel silicon waveguides and then extend this process to make multilevel beam splitters, in which three output waveguides are distributed over two depths. The dimensions of the waveguides can be defined within a range from 0.5 μm to several micrometers simply by varying the ion beam fluence.
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Alarcón H, Ynsa MD, Dang ZY, Torres-Costa V, Manso-Silván M, Wu JF, Breese MBH, García-Ruiz JP. Conditioned bio-interfaces of silicon/porous silicon micro-patterns lead to the chondrogenesis of hMSCs. RSC Adv 2015. [DOI: 10.1039/c5ra09069e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
hMSCs find attractive both Si and PSi surfaces to develop cell-surface adhesions which are needed in differentiation and the presence of CM-hMSCs bio-interface improves the differentiation process with respect to a control PSi surface.
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Affiliation(s)
- H. Alarcón
- Molecular Biology Department
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - M. D. Ynsa
- Department of Applied Physics and Instituto Nicolás Cabrera
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
- Centro de Micro-Análisis de Materiales (CMAM)
| | - Z. Y. Dang
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - V. Torres-Costa
- Department of Applied Physics and Instituto Nicolás Cabrera
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
- Centro de Micro-Análisis de Materiales (CMAM)
| | - M. Manso-Silván
- Department of Applied Physics and Instituto Nicolás Cabrera
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - J. F. Wu
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - M. B. H. Breese
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - J. P. García-Ruiz
- Molecular Biology Department
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
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Banas A, Banas K, Furgal-Borzych A, Kwiatek WM, Pawlicki B, Breese MBH. The pituitary gland under infrared light – in search of a representative spectrum for homogeneous regions. Analyst 2015; 140:2156-63. [DOI: 10.1039/c4an01985g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This work focuses on obtaining unique representative FTIR spectrum characteristic for one type of cells architecture. Presented idea is based on using of HCA for data evaluation to search for uniform patterns within samples from the perspective of FTIR spectra.
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Affiliation(s)
- A. Banas
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
| | - K. Banas
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
| | - A. Furgal-Borzych
- Department of Histology
- Jagiellonian University Medical College
- 31-034 Krakow
- Poland
| | | | - B. Pawlicki
- Gabriel Narutowicz Hospital
- 31-202 Krakow
- Poland
| | - M. B. H. Breese
- Singapore Synchrotron Light Source
- National University of Singapore
- Singapore 117603
- Singapore
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Ynsa MD, Dang ZY, Manso-Silvan M, Song J, Azimi S, Wu JF, Liang HD, Torres-Costa V, Punzon-Quijorna E, Breese MBH, Garcia-Ruiz JP. Reprogramming hMSCs morphology with silicon/porous silicon geometric micro-patterns. Biomed Microdevices 2014; 16:229-36. [PMID: 24305875 DOI: 10.1007/s10544-013-9826-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Geometric micro-patterned surfaces of silicon combined with porous silicon (Si/PSi) have been manufactured to study the behaviour of human Mesenchymal Stem Cells (hMSCs). These micro-patterns consist of regular silicon hexagons surrounded by spaced columns of silicon equilateral triangles separated by PSi. The results show that, at an early culture stage, the hMSCs resemble quiescent cells on the central hexagons with centered nuclei and actin/β-catenin and a microtubules network denoting cell adhesion. After 2 days, hMSCs adapted their morphology and cytoskeleton proteins from cell-cell dominant interactions at the center of the hexagonal surface. This was followed by an intermediate zone with some external actin fibres/β-catenin interactions and an outer zone where the dominant interactions are cell-silicon. Cells move into silicon columns to divide, migrate and communicate. Furthermore, results show that Runx2 and vitamin D receptors, both specific transcription factors for skeleton-derived cells, are expressed in cells grown on micropatterned silicon under all observed circumstances. On the other hand, non-phenotypic alterations are under cell growth and migration on Si/PSi substrates. The former consideration strongly supports the use of micro-patterned silicon surfaces to address pending questions about the mechanisms of human bone biogenesis/pathogenesis and the study of bone scaffolds.
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Affiliation(s)
- M D Ynsa
- Department of Applied Physics, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain,
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Azimi S, Song J, Li CJ, Mathew S, Breese MBH, Venkatesan T. Nanoscale lithography of LaAlO₃/SrTiO₃ wires using silicon stencil masks. Nanotechnology 2014; 25:445301. [PMID: 25302579 DOI: 10.1088/0957-4484/25/44/445301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have developed a process to fabricate low-stress, fully crystalline silicon nanostencils, based on ion irradiation and the electrochemical anodization of p-type silicon. These nanostencils can be patterned with arbitrary feature shapes with openings hundreds of micrometers wide connected to long channels of less than 100 nm in width. These nanostencils have been used to deposit (2.5 μm- to 150 nm-wide) lines of LaAlO3 (LAO) on a SrTiO3 (STO) substrate, forming a confined electron layer at the interface arising from oxygen vacancies on the STO surface. Electrical characterization of the transport properties of the resulting LAO/STO nanowires exhibited a large electric field effect through back-gating using the STO as the dielectric, demonstrating electron confinement. Stencil lithography incorporating multiple feature sizes in a single mask shows great potential for future development of oxide electronics.
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Affiliation(s)
- S Azimi
- Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore, Singapore 11754222. Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603
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Azimi S, Dang ZY, Ansari K, Breese MBH. Fabrication of silicon molds with multi-level, non-planar, micro- and nano-scale features. Nanotechnology 2014; 25:375301. [PMID: 25148117 DOI: 10.1088/0957-4484/25/37/375301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A method for single-step fabrication of arbitrary, complex, three-dimensional (3D) silicon structures from the nano- to millimeter-scale at multiple levels on non-planar, curved, or domed surfaces is reported. The fabrication is based on focused or masked ion beam irradiation of p-type silicon followed by electrochemical anodization. The process allows fabrication of a wide range of surface features at multiple heights and with arbitrary orientations by varying the irradiated feature width, ion type, energy fluence, and subsequent anodization conditions. The technology has achieved depth resolution of 10 nm as step heights and is capable of creating lateral features down to 7 nm at high aspect ratios of up to 40, with surface roughness down to 1 nm scaled up to full wafer areas. The single-step ability has seamlessly interfaced a network of complex, integrated micro- to nano-structures in 3D orientations with no alignment required. The final template has been converted to a master copy for nano-imprinting lithography of 3D fluidic structures and optical components.
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Affiliation(s)
- S Azimi
- Department of Physics, National University of Singapore, Singapore 117542, Singapore. Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, Singapore 117603, Singapore
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14
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Rusydi A, Goos A, Binder S, Eich A, Botril K, Abbamonte P, Yu X, Breese MBH, Eisaki H, Fujimaki Y, Uchida S, Guerassimova N, Treusch R, Feldhaus J, Reininger R, Klein MV, Rübhausen M. Electronic screening-enhanced hole pairing in two-leg spin ladders studied by high-resolution resonant inelastic x-ray scattering at Cu M edges. Phys Rev Lett 2014; 113:067001. [PMID: 25148343 DOI: 10.1103/physrevlett.113.067001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Indexed: 05/23/2023]
Abstract
We study the electronic screening mechanisms of the effective Coulomb on-site repulsion in hole-doped Sr(14)Cu(24)O(41) compared to undoped La(6)Ca(8)Cu(24)O(41) using polarization dependent high-resolution resonant inelastic x-ray scattering at Cu M edges. By measuring the energy of the effective Coulomb on-site repulsion and the spin excitations, we estimate superexchange and hopping matrix element energies along rungs and legs, respectively. Interestingly, hole doping locally screens the Coulomb on-site repulsion reducing it by as much as 25%. We suggest that the increased ratio of the electronic kinetic to the electronic correlation energy contributes to the local superexchange mediated pairing between holes.
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Affiliation(s)
- A Rusydi
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore
| | - A Goos
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany
| | - S Binder
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany
| | - A Eich
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany
| | - K Botril
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany
| | - P Abbamonte
- Physics Department and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - X Yu
- Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore
| | - M B H Breese
- NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore
| | - H Eisaki
- Nanoelectronics Research Institute, AIST, 1-1-1 Central 2, Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Y Fujimaki
- Department of Superconductivity, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
| | - S Uchida
- Department of Superconductivity, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
| | - N Guerassimova
- Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | - R Treusch
- Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | - J Feldhaus
- Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | - R Reininger
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M V Klein
- Physics Department and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA
| | - M Rübhausen
- Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore
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Abstract
We have studied the formation of buried, hollow channels in oxidized porous silicon produced by a process based on focused high-energy ion irradiation of low resistivity, p-type silicon.
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Affiliation(s)
- Z. Y. Dang
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - D. Q. Liu
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - S. Azimi
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
| | - M. B. H. Breese
- Centre for Ion Beam Applications (CIBA)
- Department of Physics
- National University of Singapore
- Singapore 117542
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Rusydi A, Dhar S, Barman AR, Qi DC, Motapothula M, Yi JB, Santoso I, Feng YP, Yang K, Dai Y, Yakovlev NL, Ding J, Wee ATS, Neuber G, Breese MBH, Ruebhausen M, Hilgenkamp H, Venkatesan T. Cationic-vacancy-induced room-temperature ferromagnetism in transparent, conducting anatase Ti1-xTaxO2 (x~0.05) thin films. Philos Trans A Math Phys Eng Sci 2012; 370:4927-4943. [PMID: 22987036 DOI: 10.1098/rsta.2012.0198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report room-temperature ferromagnetism (FM) in highly conducting, transparent anatase Ti(1-x)Ta(x)O(2) (x∼0.05) thin films grown by pulsed laser deposition on LaAlO(3) substrates. Rutherford backscattering spectrometry (RBS), X-ray diffraction, proton-induced X-ray emission, X-ray absorption spectroscopy (XAS) and time-of-flight secondary-ion mass spectrometry indicated negligible magnetic contaminants in the films. The presence of FM with concomitant large carrier densities was determined by a combination of superconducting quantum interference device magnetometry, electrical transport measurements, soft X-ray magnetic circular dichroism (SXMCD), XAS and optical magnetic circular dichroism, and was supported by first-principles calculations. SXMCD and XAS measurements revealed a 90 per cent contribution to FM from the Ti ions, and a 10 per cent contribution from the O ions. RBS/channelling measurements show complete Ta substitution in the Ti sites, though carrier activation was only 50 per cent at 5 per cent Ta concentration, implying compensation by cationic defects. The role of the Ti vacancy (V(Ti)) and Ti(3+) was studied via XAS and X-ray photoemission spectroscopy, respectively. It was found that, in films with strong FM, the V(Ti) signal was strong while the Ti(3+) signal was absent. We propose (in the absence of any obvious exchange mechanisms) that the localized magnetic moments, V(Ti) sites, are ferromagnetically ordered by itinerant carriers. Cationic-defect-induced magnetism is an alternative route to FM in wide-band-gap semiconducting oxides without any magnetic elements.
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Affiliation(s)
- A Rusydi
- NUSNNI-NanoCore, National University of Singapore, Republic of Singapore.
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Motapothula M, Dang ZY, Venkatesan T, Breese MBH, Rana MA, Osman A. Influence of the narrow {111} planes on axial and planar ion channeling. Phys Rev Lett 2012; 108:195502. [PMID: 23003055 DOI: 10.1103/physrevlett.108.195502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Indexed: 06/01/2023]
Abstract
We report channeling patterns where clearly resolved effects of the narrow {111} planes are observed in axial and planar alignments for 2 MeV protons passing through a 55 nm [001] silicon membrane. At certain axes, such as <213> and <314>, the offset in atomic rows forming the narrow {111} planes results in shielding from the large potential at the wide {111} planes, producing a region of shallow, asymmetric potential from which axial channeling patterns have no plane of symmetry. At small tilts from such axes, different behavior is observed from the wide and narrow {111} planes. At planar alignment, distinctive channeling effects due to the narrow planes are observed. As a consequence of the shallow potential well at the narrow planes, incident protons suffer dechanneled trajectories which are excluded from channeling within the wide planes, resulting in an anomalously large scattered beam at {111} alignment.
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Affiliation(s)
- M Motapothula
- Center for Ion Beam Applications, Physics Department, National University of Singapore, Lower Kent Ridge Road, Singapore 117542
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Banas A, Banas K, Breese MBH, Loke J, Heng Teo B, Lim SK. Detection of microscopic particles present as contaminants in latent fingerprints by means of synchrotron radiation-based Fourier transform infra-red micro-imaging. Analyst 2012; 137:3459-65. [DOI: 10.1039/c2an35355e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Teo EJ, Xiong BQ, Ow YS, Breese MBH, Bettiol AA. Effects of oxide formation around core circumference of silicon-on-oxidized-porous-silicon strip waveguides. Opt Lett 2009; 34:3142-3144. [PMID: 19838253 DOI: 10.1364/ol.34.003142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We have studied the effect of oxidation on the propagation loss and surface roughness of silicon-on-oxidized-porous-silicon strip waveguides fabricated using proton-beam irradiation and electrochemical etching. A thin thermal oxide is formed around the core of the waveguide, enabling the symmetric reduction of core size and roughness on all sides. Significant loss reduction from about 10 dB/cm to 1 dB/cm has been obtained in TE and TM polarizations after oxidation smoothening of both the bottom and the sidewalls by 20 nm. This corresponds well with simulations using the beam-propagation method that show significant contributions from both surfaces.
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Affiliation(s)
- E J Teo
- Centre for Ion Beam Applications, Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore.
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Luo D, Sun XW, Liu YJ, Dai HT, Sheng OY, Breese MBH, Raszewski Z. Electrically switchable computer-generated hologram using a liquid crystal cell with a proton beam patterned polymethylmethacrylate substrate. Appl Opt 2009; 48:3766-3770. [PMID: 19571935 DOI: 10.1364/ao.48.003766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An electrically switchable computer-generated hologram (CGH) was fabricated using a liquid crystal (LC) cell. A polymethylmethacrylate (PMMA) film, which was spin-coated on one glass substrate of the LC cell, was patterned by a focused 2 MeV proton beam with a CGH phase pattern (2 microm resolution). With an applied voltage on the LC cell CGH sample, an index modulation was produced between the regions with and without PMMA because of the reorientation of LC molecules under the external electric field. The maximum diffraction efficiency measured was about 28.7%. The operating voltage was below 15 V(rms).
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Affiliation(s)
- D Luo
- School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore
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21
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Teo EJ, Bettiol AA, Yang P, Breese MBH, Xiong BQ, Mashanovich GZ, Headley WR, Reed GT. Fabrication of low-loss silicon-on-oxidized-porous-silicon strip waveguide using focused proton-beam irradiation. Opt Lett 2009; 34:659-661. [PMID: 19252584 DOI: 10.1364/ol.34.000659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have successfully fabricated low-loss silicon-on-oxidized-porous-silicon (SOPS) strip waveguides with high-index contrast using focused proton-beam irradiation and electrochemical etching. Smooth surface quality with rms roughness of 3.1 nm is achieved for a fluence of 1x10(15)/cm(2) after postoxidation treatment. Optical characterization at a wavelength of 1550 nm shows a loss of 1.1+/-0.4 dB/cm and 1.2+/-0.4 dB/cm in TE and TM polarization respectively, which we believe is the lowest reported loss for SOPS waveguides. This opens up new opportunities for all-silicon-based optoelectronics applications.
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Affiliation(s)
- E J Teo
- Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore.
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Breese MBH, Mangaiyarkarasi D, Teo EJ, Bettiol AA, Blackwood D. Micro-patterned porous silicon using proton beam writing. ACTA ACUST UNITED AC 2006. [DOI: 10.1063/1.2401510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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23
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Breese MBH, Rana MA, Osipowicz T, Teo EJ. Enhanced planar channeling of MeV protons through thin crystals. Phys Rev Lett 2004; 93:105505. [PMID: 15447418 DOI: 10.1103/physrevlett.93.105505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Indexed: 05/24/2023]
Abstract
At certain tilt alignments between a MeV proton beam and a planar channeling direction, a single interface lattice rotation within a crystal can result in a lower rate of dechanneling than at planar alignment in a perfect crystal. Such planar channeling enhancement arises when the beam passes through a layer thickness which is a half-multiple of the oscillation wavelength and then encounters a small interface rotation which is matched to the beam tilt angle. The beam is projected into the center of the phase space ellipse below the interface, resulting in certain trajectories undergoing a reduction in their transverse energy, in a manner analogous to stochastic cooling or atom laser cooling.
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Affiliation(s)
- M B H Breese
- Physics Department, National University of Singapore, 10 Lower Kent Ridge Road, Singapore 119260
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24
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Breese MBH, Teo EJ, Rana MA, Huang L, van Kan JA, Watt F, King PJC. Observation of many coherent oscillations for MeV protons transmitted through stacking faults. Phys Rev Lett 2004; 92:045503. [PMID: 14995385 DOI: 10.1103/physrevlett.92.045503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2003] [Indexed: 05/24/2023]
Abstract
High spatial resolution, high-contrast transmission channeling images of stacking faults in silicon have been produced using a beam of 2 MeV protons focused to a spot size of 60 nm. Over a narrow range of beam tilts to the (011) planes, up to ten periodic intensity oscillations are observed, providing evidence of a long-range coherency of the planar channeled trajectories. This behavior is characterized using Monte Carlo computer simulations, and a phase-space model of planar channeled ion interactions with stacking faults is developed which incorporates all observed channeling and blocking phenomena.
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Affiliation(s)
- M B H Breese
- Physics Department, National University of Singapore, 10 Lower Kent Ridge Road, Singapore 119260
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