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Zakaria MB, Nagata T, Chikyow T. Mesostructured HfO 2/Al 2O 3 Composite Thin Films with Reduced Leakage Current for Ion-Conducting Devices. ACS OMEGA 2019; 4:14680-14687. [PMID: 31552307 PMCID: PMC6751548 DOI: 10.1021/acsomega.9b01095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Mesoporous hafnium dioxide (HfO2) thin films (around 20 nm thick) were fabricated by a sol-gel-based spin-coating process, followed by an annealing process at 600 °C to realize the ion-conducting media for the ionics (e.g., Na+ and K+ for rechargeable ion batteries). Another film of aluminum metal (10 nm thick) was deposited by direct current sputtering to soak into the mesopores. A monitored thermal treatment process at 500 °C in the air yields mesostructured HfO2/Al2O3 composite thin films. However, aluminum dioxide (Al2O3) is formed during annealing as an insulating film to reduce the leakage current while retaining the ionic conductivity. The obtained mesostructured HfO2/Al2O3 films show a leakage current at 3.2 × 10-9 A cm-2, which is significantly smaller than that of the mesoporous HfO2 film (1.37 × 10-5 A cm-2) or HfO2/Al film (0.037 A cm-2) at a bias voltage of 1.0 V, which is enough for ion conduction. In the meantime, among all the thin films, the mesostructured HfO2/Al2O3 composite thin films display the smallest Nyquist arc diameter in 1.0 M KOH electrolyte, implying a lower impedance at the electrode/electrolyte interface and reflecting a better ion diffusion and movement.
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Affiliation(s)
- Mohamed Barakat Zakaria
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Department
of Chemistry, Faculty of Science, Tanta
University, Tanta, Gharbeya 31527, Egypt
| | - Takahiro Nagata
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Toyohiro Chikyow
- International
Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Materials
Data & Integrated System (MaDIS), National
Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
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2
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Qi Z, Sun H, Luo M, Jung Y, Nam D. Strained germanium nanowire optoelectronic devices for photonic-integrated circuits. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:334004. [PMID: 29968583 DOI: 10.1088/1361-648x/aad0c0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Strained germanium nanowires have recently become an important material of choice for silicon-compatible optoelectronic devices. While the indirect bandgap nature of germanium had long been problematic both in light absorption and emission, recent successful demonstrations of bandstructure engineering by elastic strain have opened up the possibility of achieving direct bandgap in germanium, paving the way towards the realization of various high-performance optical devices integrated on a silicon platform. In particular, the latest demonstration of a low-threshold optically pumped laser in a highly strained germanium nanowire is expected to vitalize the field of silicon photonics further. Here, we review recent advances and challenges in strained germanium nanowires for optoelectronic applications such as photodetectors and lasers. We firstly introduce the theoretical foundation behind strained germanium nanowire optoelectronics. And several practical approaches that have been proposed to apply tensile strain in germanium nanowires are further discussed. Then we address the latest progress in the developments of strained germanium nanowire optoelectronic devices. Finally, we discuss the implications of these experimental achievements and the future outlook in this promising research field.
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Affiliation(s)
- Zhipeng Qi
- School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore
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3
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Basu T, Kumar M, Saini M, Ghatak J, Satpati B, Som T. Surfing Silicon Nanofacets for Cold Cathode Electron Emission Sites. ACS APPLIED MATERIALS & INTERFACES 2017; 9:38931-38942. [PMID: 29019387 DOI: 10.1021/acsami.7b08738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Point sources exhibit low threshold electron emission due to local field enhancement at the tip. In the case of silicon, however, the realization of tip emitters has been hampered by unwanted oxidation, limiting the number of emission sites and the overall current. In contrast to this, here, we report the fascinating low threshold (∼0.67 V μm-1) cold cathode electron emission from silicon nanofacets (Si-NFs). The ensembles of nanofacets fabricated at different time scales, under low energy ion impacts, yield tunable field emission with a Fowler-Nordheim tunneling field in the range of 0.67-4.75 V μm-1. The local probe surface microscopy-based tunneling current mapping in conjunction with Kelvin probe force microscopy measurements revealed that the valleys and a part of the sidewalls of the nanofacets contribute more to the field emission process. The observed lowest turn-on field is attributed to the absence of native oxide on the sidewalls of the smallest facets as well as their lowest work function. In addition, first-principle density functional theory-based simulation revealed a crystal orientation-dependent work function of Si, which corroborates well with our experimental observations. The present study demonstrates a novel way to address the origin of the cold cathode electron emission sites from Si-NFs fabricated at room temperature. In principle, the present methodology can be extended to probe the cold cathode electron emission sites from any nanostructured material.
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Affiliation(s)
- Tanmoy Basu
- SUNAG Laboratory, Institute of Physics , Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400085, India
| | - Mohit Kumar
- SUNAG Laboratory, Institute of Physics , Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400085, India
| | - Mahesh Saini
- SUNAG Laboratory, Institute of Physics , Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400085, India
| | - Jay Ghatak
- SUNAG Laboratory, Institute of Physics , Sachivalaya Marg, Bhubaneswar 751005, India
| | - Biswarup Satpati
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400085, India
- Saha Institute of Nuclear Physics , 1/AF Bidhannagar, Kolkata 700064, India
| | - Tapobrata Som
- SUNAG Laboratory, Institute of Physics , Sachivalaya Marg, Bhubaneswar 751005, India
- Homi Bhabha National Institute , Training School Complex, Anushakti Nagar, Mumbai 400085, India
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4
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Hu Y, Li J, Tian J, Xuan Y, Deng B, McNear KL, Lim DG, Chen Y, Yang C, Cheng GJ. Parallel Nanoshaping of Brittle Semiconductor Nanowires for Strained Electronics. NANO LETTERS 2016; 16:7536-7544. [PMID: 27960457 DOI: 10.1021/acs.nanolett.6b03366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Semiconductor nanowires (SCNWs) provide a unique tunability of electro-optical property than their bulk counterparts (e.g., polycrystalline thin films) due to size effects. Nanoscale straining of SCNWs is desirable to enable new ways to tune the properties of SCNWs, such as electronic transport, band structure, and quantum properties. However, there are two bottlenecks to prevent the real applications of straining engineering of SCNWs: strainability and scalability. Unlike metallic nanowires which are highly flexible and mechanically robust for parallel shaping, SCNWs are brittle in nature and could easily break at strains slightly higher than their elastic limits. In addition, the ability to generate nanoshaping in large scale is limited with the current technologies, such as the straining of nanowires with sophisticated manipulators, nanocombing NWs with U-shaped trenches, or buckling NWs with prestretched elastic substrates, which are incompatible with semiconductor technology. Here we present a top-down fabrication methodology to achieve large scale nanoshaping of SCNWs in parallel with tunable elastic strains. This method utilizes nanosecond pulsed laser to generate shock pressure and conformably deform the SCNWs onto 3D-nanostructured silicon substrates in a scalable and ultrafast manner. A polymer dielectric nanolayer is integrated in the process for cushioning the high strain-rate deformation, suppressing the generation of dislocations or cracks, and providing self-preserving mechanism for elastic strain storage in SCNWs. The elastic strain limits have been studied as functions of laser intensity, dimensions of nanowires, and the geometry of nanomolds. As a result of 3D straining, the inhomogeneous elastic strains in GeNWs result in notable Raman peak shifts and broadening, which bring more tunability of the electrical-optical property in SCNWs than traditional strain engineering. We have achieved the first 3D nanostraining enhanced germanium field-effect transistors from GeNWs. Due to laser shock induced straining effect, a more than 2-fold hole mobility enhancement and a 120% transconductance enhancement are obtained from the fabricated back-gated field effect transistors. The presented nanoshaping of SCNWs provide new ways to manipulate nanomaterials with tunable electrical-optical properties and open up many opportunities for nanoelectronics, the nanoelectrical-mechanical system, and quantum devices.
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Affiliation(s)
- Yaowu Hu
- School of Industrial Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Ji Li
- School of Industrial Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Jifa Tian
- Department of Physics, Purdue University , West Lafayette, Indiana 47907, United States
| | - Yi Xuan
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Biwei Deng
- School of Industrial Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Kelly L McNear
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
| | - Daw Gen Lim
- School of Materials Engineering, Purdue University , West Lafayette, Indiana 47907, United States
| | - Yong Chen
- Department of Physics, Purdue University , West Lafayette, Indiana 47907, United States
| | - Chen Yang
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
- Department of Physics, Purdue University , West Lafayette, Indiana 47907, United States
| | - Gary J Cheng
- School of Industrial Engineering, Purdue University , West Lafayette, Indiana 47907, United States
- Birck Nanotechnology Center, Purdue University , West Lafayette, Indiana 47907, United States
- School of Mechanical Engineering, Purdue University , West Lafayette, Indiana 47907, United States
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Ameer FS, Varahagiri S, Benza DW, Willett DR, Wen Y, Wang F, Chumanov G, Anker JN. Tuning Localized Surface Plasmon Resonance Wavelengths of Silver Nanoparticles by Mechanical Deformation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2016; 120:20886-20895. [PMID: 28239431 PMCID: PMC5325716 DOI: 10.1021/acs.jpcc.6b02169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We describe a simple technique to alter the shape of silver nanoparticles (AgNPs) by rolling a glass tube over them to mechanically compress them. The resulting shape change in turn induces a red-shift in the localized surface plasmon resonance (LSPR) scattering spectrum and exposes new surface area. The flattened particles were characterized by optical and electron microscopy, single nanoparticle scattering spectroscopy, and surface enhanced Raman spectroscopy (SERS). AFM and SEM images show that the AgNPs deform into discs; increasing the applied load from 0 to 100 N increases the AgNP diameter and decreases the height. This deformation caused a dramatic red shift in the nanoparticle scattering spectrum and also generated new surface area to which thiolated molecules could attach as evident from SERS measurements. The simple technique employed here requires no lithographic templates and has potential for rapid, reproducible, inexpensive and scalable tuning of nanoparticle shape, surface area, and resonance while preserving particle volume.
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Affiliation(s)
- Fathima S Ameer
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - Shilpa Varahagiri
- Department of Chemistry, Clemson University, Clemson SC 29634; Department of Mechanical Engineering, Clemson University, Clemson SC 29634
| | - Donald W Benza
- Department of Chemistry, Clemson University, Clemson SC 29634; Department of Electrical and Computer Engineering, Clemson University, Clemson SC 29634
| | | | - Yimei Wen
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - Fenglin Wang
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - George Chumanov
- Department of Chemistry, Clemson University, Clemson SC 29634
| | - Jeffrey N Anker
- Department of Chemistry, Clemson University, Clemson SC 29634; Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson SC 29634
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6
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Shao R, Gao P, Zheng K. The effect of tensile and bending strain on the electrical properties of p-type 〈110〉 silicon nanowires. NANOTECHNOLOGY 2015; 26:265703. [PMID: 26059313 DOI: 10.1088/0957-4484/26/26/265703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this study, electromechanical responses induced by uniaxial tensile and bending deformation were obtained for p-type 〈110〉-oriented Si whiskers by in situ transmission electron microscopy (TEM). Ohmic contacts between the nanowires (NWs) and electrodes were achieved using electron-beam-induced carbon deposition. Results show that enhancements in the carrier transport properties were achieved under both uniaxial tensile and bending strains. With the strain increased to 1.5% before fracture, the improvement in the conductance reached a maximum, which was as large as 24.2%, without any sign of saturation. On the other hand, under 5.8% bending strain, a 67% conductivity enhancement could be achieved. This study should provide important insight into the performance of nanoscale-strained Si.
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Affiliation(s)
- Ruiwen Shao
- Institute of Microstructure and Properties of Advanced Materials, Beijing University of Technology, Beijing 100124, People's Republic of China
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7
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Zhang C, Li C, Liu Z, Zheng J, Xue C, Zuo Y, Cheng B, Wang Q. Enhanced photoluminescence from porous silicon nanowire arrays. NANOSCALE RESEARCH LETTERS 2013; 8:277. [PMID: 23758957 PMCID: PMC3683345 DOI: 10.1186/1556-276x-8-277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 06/02/2013] [Indexed: 06/01/2023]
Abstract
The enhanced room-temperature photoluminescence of porous Si nanowire arrays and its mechanism are investigated. Over 4 orders of magnitude enhancement of light intensity is observed by tuning their nanostructures and surface modification. It is concluded that the localized states related to Si-O bonds and self-trapped excitations in the nanoporous structures are attributed to the strong light emission.
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Affiliation(s)
- Chunqian Zhang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Chuanbo Li
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Zhi Liu
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Jun Zheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Chunlai Xue
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Yuhua Zuo
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Buwen Cheng
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
| | - Qiming Wang
- State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
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8
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Zhang L, d'Avezac M, Luo JW, Zunger A. Genomic design of strong direct-gap optical transition in Si/Ge core/multishell nanowires. NANO LETTERS 2012; 12:984-991. [PMID: 22216831 DOI: 10.1021/nl2040892] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Finding a Si-based material with strong optical activity at the band-edge remains a challenge despite decades of research. The interest lies in combining optical and electronic functions on the same wafer, while retaining the extraordinary know-how developed for Si. However, Si is an indirect-gap material. The conservation of crystal momentum mandates that optical activity at the band-edge includes a phonon, on top of an electron-hole pair, and hence photon absorption and emission remain fairly unlikely events requiring optically rather thick samples. A promising avenue to convert Si-based materials to a strong light-absorber/emitter is to combine the effects on the band-structure of both nanostructuring and alloying. The number of possible configurations, however, shows a combinatorial explosion. Furthermore, whereas it is possible to readily identify the configurations that are formally direct in the momentum space (due to band-folding) yet do not have a dipole-allowed transition at threshold, the problem becomes not just calculation of band structure but also calculation of absorption strength. Using a combination of a genetic algorithm and a semiempirical pseudopotential Hamiltonian for describing the electronic structures, we have explored hundreds of thousands of possible coaxial core/multishell Si/Ge nanowires with the orientation of [001], [110], and [111], discovering some "magic sequences" of core followed by specific Si/Ge multishells, which can offer both a direct bandgap and a strong oscillator strength. The search has revealed a few simple design principles: (i) the Ge core is superior to the Si core in producing strong bandgap transition; (ii) [001] and [110] orientations have direct bandgap, whereas the [111] orientation does not; (iii) multishell nanowires can allow for greater optical activity by as much as an order of magnitude over plain nanowires; (iv) the main motif of the winning configurations giving direct allowed transitions involves rather thin Si shell embedded within wide Ge shells. We discuss the physical origin of the enhanced optical activity, as well as the effect of possible experimental structural imperfections on optical activity in our candidate core/multishell nanowires.
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Affiliation(s)
- Lijun Zhang
- National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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9
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Zhang RQ, Hou C, Gao N, Wen Z, Jiang Q. Multi‐Field Effect on the Electronic Properties of Silicon Nanowires. Chemphyschem 2011; 12:1302-9. [DOI: 10.1002/cphc.201100030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 03/04/2011] [Indexed: 11/09/2022]
Affiliation(s)
- Ren Qin Zhang
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022 (China), Fax: (+86) 431‐85095876
| | - Chao Hou
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022 (China), Fax: (+86) 431‐85095876
| | - Nan Gao
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022 (China), Fax: (+86) 431‐85095876
| | - Zi Wen
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022 (China), Fax: (+86) 431‐85095876
| | - Qing Jiang
- Key Laboratory of Automobile Materials (Jilin University), Ministry of Education, and School of Materials Science and Engineering, Jilin University, Changchun, 130022 (China), Fax: (+86) 431‐85095876
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10
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Peng X, Tang F, Logan P. Band structure of Si/Ge core-shell nanowires along the [110] direction modulated by external uniaxial strain. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:115502. [PMID: 21358032 DOI: 10.1088/0953-8984/23/11/115502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Strain modulated electronic properties of Si/Ge core-shell nanowires along the [110] direction were reported, on the basis of first principles density-functional theory calculations. In particular, the energy dispersion relationship of the conduction/valence band was explored in detail. At the Γ point, the energy levels of both bands are significantly altered by applied uniaxial strain, which results in an evident change of the band gap. In contrast, for the K vectors far away from Γ, the variation of the conduction/valence band with strain is much reduced. In addition, with a sufficient tensile strain (∼1%), the valence band edge shifts away from Γ, which indicates that the band gap of the Si/Ge core-shell nanowires experiences a transition from direct to indirect. Our studies further showed that effective masses of charge carriers can also be tuned using the external uniaxial strain. The effective mass of the hole increases dramatically with tensile strain, while strain shows a minimal effect on tuning the effective mass of the electron. Finally, the relation between strain and the conduction/valence band edge is discussed thoroughly in terms of site-projected wavefunction characters.
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Affiliation(s)
- Xihong Peng
- Department of Applied Sciences and Mathematics, Arizona State University, Mesa, AZ 85212, USA
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11
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Walavalkar SS, Hofmann CE, Homyk AP, Henry MD, Atwater HA, Scherer A. Tunable visible and near-IR emission from sub-10 nm etched single-crystal Si nanopillars. NANO LETTERS 2010; 10:4423-8. [PMID: 20919695 DOI: 10.1021/nl102140k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Visible and near-IR photoluminescence (PL) is reported from sub-10 nm silicon nanopillars. Pillars were plasma etched from single crystal Si wafers and thinned by utilizing strain-induced, self-terminating oxidation of cylindrical structures. PL, lifetime, and transmission electron microscopy were performed to measure the dimensions and emission characteristics of the pillars. The peak PL energy was found to blue shift with narrowing pillar diameter in accordance with a quantum confinement effect. The blue shift was quantified using a tight binding method simulation that incorporated the strain induced by the thermal oxidation process. These pillars show promise as possible complementary metal oxide semiconductor compatible silicon devices in the form of light-emitting diode or laser structures.
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Affiliation(s)
- Sameer S Walavalkar
- Applied Physics Department, California Institute of Technology, 1200 East California Boulevard MC 200-36 Pasadena California 91125, United States.
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Han X, Kou L, Lang X, Xia J, Wang N, Qin R, Lu J, Xu J, Liao Z, Zhang X, Shan X, Song X, Gao J, Guo W, Yu D. Electronic and Mechanical Coupling in Bent ZnO Nanowires. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2009; 21:4937-4941. [PMID: 25376615 DOI: 10.1002/adma.200900956] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Indexed: 05/15/2023]
Abstract
A red shift of the exciton of ZnO nanowires is efficiently produced by bending strain, as demonstrated by a low-temperature (81 K) cathodoluminescence (CL) study of ZnO nanowires bent into L- or S-shapes. The figure shows a nanowire (Fig. a) with the positions of CL measurements marked. The corresponding CL spectra-revealing a peak shift and broadening in the region of the bend-are shown in Figure b.
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Affiliation(s)
- Xiaobing Han
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Liangzhi Kou
- Institute of Nanoscience Nanjing University of Aeronautics and Astronautics Nanjing 210016 (P. R. China)
| | - Xiaoli Lang
- State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors, Chinese Academy of Sciences PO Box 912, Beijing 100083 (P. R. China)
| | - Jianbai Xia
- State Key Laboratory for Superlattices and Microstructures Institute of Semiconductors, Chinese Academy of Sciences PO Box 912, Beijing 100083 (P. R. China)
| | - Ning Wang
- Physics Department Hong Kong University of Science and Technology ClearWater Bay, Kowloon, Hong Kong (Hong Kong)
| | - Rui Qin
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Jing Lu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Jun Xu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Zhimin Liao
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Xinzheng Zhang
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Xudong Shan
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Xuefeng Song
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Jingyun Gao
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
| | - Wanlin Guo
- Institute of Nanoscience Nanjing University of Aeronautics and Astronautics Nanjing 210016 (P. R. China)
| | - Dapeng Yu
- State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory Department of Physics, Peking University Beijing 100871 (P. R. China)
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Pan C, Zhu J. The syntheses, properties and applications of Si, ZnO, metal, and heterojunction nanowires. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b816463k] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Hong KH, Kim J, Lee SH, Shin JK. Strain-driven electronic band structure modulation of si nanowires. NANO LETTERS 2008; 8:1335-40. [PMID: 18402477 DOI: 10.1021/nl0734140] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
One of the major challenges toward Si nanowire (SiNW) based photonic devices is controlling the electronic band structure of the Si nanowire to obtain a direct band gap. Here, we present a new strategy for controlling the electronic band structure of Si nanowires. Our method is attributed to the band structure modulation driven by uniaxial strain. We show that the band structure modulation with lattice strain is strongly dependent on the crystal orientation and diameter of SiNWs. In the case of [100] and [111] SiNWs, tensile strain enhances the direct band gap characteristic, whereas compressive strain attenuates it. [110] SiNWs have a different strain dependence in that both compressive and tensile strain make SiNWs exhibit an indirect band gap. We discuss the origin of this strain dependence based on the band features of bulk silicon and the wave functions of SiNWs. These results could be helpful for band structure engineering and analysis of SiNWs in nanoscale devices.
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Affiliation(s)
- Ki-Ha Hong
- Samsung Advanced Institute of Technology, Mt. 14-1, Nongseo-Dong, Giheung-Gu, Yongin-Si, Gyeonggi-Do, 446-712, Korea.
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Fang X, Bando Y, Gautam UK, Ye C, Golberg D. Inorganic semiconductor nanostructures and their field-emission applications. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b712874f] [Citation(s) in RCA: 552] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Gerung H, Boyle TJ, Tribby LJ, Bunge SD, Brinker CJ, Han SM. Solution synthesis of germanium nanowires using a Ge2+ alkoxide precursor. J Am Chem Soc 2007; 128:5244-50. [PMID: 16608360 PMCID: PMC2538547 DOI: 10.1021/ja058524s] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A simple solution synthesis of germanium (Ge0) nanowires under mild conditions (<400 degrees C and 1 atm) was demonstrated using germanium 2,6-dibutylphenoxide, Ge(DBP)2 (1), as the precursor where DBP = 2,6-OC6H3(C(CH3)3)2. Compound 1, synthesized from Ge(NR2)2 where R = SiMe3 and 2 equiv of DBP-H, was characterized as a mononuclear species by single-crystal X-ray diffraction. Dissolution of 1 in oleylamine, followed by rapid injection into a 1-octadecene solution heated to 300 degrees C under an atmosphere of Ar, led to the formation of Ge0 nanowires. The Ge0 nanowires were characterized by transmission electron microscopy (TEM), X-ray diffraction analysis, and Fourier transform infrared spectroscopy. These characterizations revealed that the nanowires are single crystalline in the cubic phase and coated with oleylamine surfactant. We also observed that the nanowire length (0.1-10 microm) increases with increasing temperature (285-315 degrees C) and time (5-60 min). Two growth mechanisms are proposed based on the TEM images intermittently taken during the growth process as a function of time: (1) self-seeding mechanism where one of two overlapping nanowires serves as a seed, while the other continues to grow as a wire; and (2) self-assembly mechanism where an aggregate of small rods (<50 nm in diameter) recrystallizes on the tip of a longer wire, extending its length.
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Affiliation(s)
- Henry Gerung
- Department of Chemical and Nuclear Engineering, University of New Mexico, 209 Farris Engineering Center, Albuquerque, NM 87131
| | - Timothy J. Boyle
- Advanced Materials Laboratory, Sandia National Laboratories, 1001 University Blvd SE, Albuquerque, NM 87106
- Author to whom correspondences should be sent: Timothy J. Boyle [Ph: (505) 272-7625, Fax: (505-272-7663, E-mail: ] and Sang M. Han [Ph: (505)277-3118; Fax: (505)277-5431; ]
| | - Louis J. Tribby
- Advanced Materials Laboratory, Sandia National Laboratories, 1001 University Blvd SE, Albuquerque, NM 87106
| | - Scott D. Bunge
- Advanced Materials Laboratory, Sandia National Laboratories, 1001 University Blvd SE, Albuquerque, NM 87106
| | - C. Jeffrey Brinker
- Department of Chemical and Nuclear Engineering, University of New Mexico, 209 Farris Engineering Center, Albuquerque, NM 87131
- Advanced Materials Laboratory, Sandia National Laboratories, 1001 University Blvd SE, Albuquerque, NM 87106
| | - Sang M. Han
- Department of Chemical and Nuclear Engineering, University of New Mexico, 209 Farris Engineering Center, Albuquerque, NM 87131
- Author to whom correspondences should be sent: Timothy J. Boyle [Ph: (505) 272-7625, Fax: (505-272-7663, E-mail: ] and Sang M. Han [Ph: (505)277-3118; Fax: (505)277-5431; ]
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Audoit G, Kulkarni JS, Morris MA, Holmes JD. Size dependent thermal properties of embedded crystalline germanium nanowires. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b616216a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fang X, Bando Y, Ye C, Shen G, Gautam UK, Tang C, Golberg D. Si nanowire semisphere-like ensembles as field emitters. Chem Commun (Camb) 2007:4093-5. [DOI: 10.1039/b701113j] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Templated germanium nanowire synthesis using oriented mesoporous organosilicate thin films. ACTA ACUST UNITED AC 2006. [DOI: 10.1116/1.2244543] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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