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Gunder C, Maia de Oliveira F, Wangila E, Stanchu H, Zamani-Alavijeh M, Ojo S, Acharya S, Said A, Li C, Mazur YI, Yu SQ, Salamo GJ. The growth of Ge and direct bandgap Ge 1-xSn x on GaAs (001) by molecular beam epitaxy. RSC Adv 2024; 14:1250-1257. [PMID: 38174282 PMCID: PMC10762728 DOI: 10.1039/d3ra06774b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
Germanium tin (GeSn) is a tuneable narrow bandgap material, which has shown remarkable promise for the industry of near- and mid-infrared technologies for high efficiency photodetectors and laser devices. Its synthesis is challenged by the lattice mismatch between the GeSn alloy and the substrate on which it is grown, sensitively affecting its crystalline and optical qualities. In this article, we investigate the growth of Ge and GeSn on GaAs (001) substrates using two different buffer layers consisting of Ge/GaAs and Ge/AlAs via molecular beam epitaxy. The quality of the Ge layers was compared using X-ray diffraction, atomic force microscopy, reflection high-energy electron diffraction, and photoluminescence. The characterization techniques demonstrate high-quality Ge layers, including atomic steps, when grown on either GaAs or AlAs at a growth temperature between 500-600 °C. The photoluminescence from the Ge layers was similar in relative intensity and linewidth to that of bulk Ge. The Ge growth was followed by the growth of GeSn using a Sn composition gradient and substrate gradient approach to achieve GeSn films with 9 to 10% Sn composition. Characterization of the GeSn films also indicates high-quality gradients based on X-ray diffraction, photoluminescence, and energy-dispersive X-ray spectroscopy measurements. Finally, we were able to demonstrate temperature-dependent PL results showing that for the growth on Ge/GaAs buffer, the direct transition has shifted past the indirect transition to a longer wavelength/lower energy suggesting a direct bandgap GeSn material.
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Affiliation(s)
- Calbi Gunder
- Materials Science and Engineering, University of Arkansas Fayetteville AR 72701 USA
| | | | - Emmanuel Wangila
- Materials Science and Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Hryhorii Stanchu
- Institute of Nanoscience & Engineering, University of Arkansas Fayetteville AR 72701 USA
| | | | - Solomon Ojo
- Materials Science and Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Sudip Acharya
- Materials Science and Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Abdulla Said
- Materials Science and Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Chen Li
- Institute of Nanoscience & Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Yuriy I Mazur
- Institute of Nanoscience & Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Shui-Qing Yu
- Institute of Nanoscience & Engineering, University of Arkansas Fayetteville AR 72701 USA
- Department of Electrical Engineering, University of Arkansas Fayetteville AR 72701 USA
| | - Gregory J Salamo
- Institute of Nanoscience & Engineering, University of Arkansas Fayetteville AR 72701 USA
- Department of Physics, University of Arkansas Fayetteville AR 72701 USA
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2
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Kuzmin M, Lehtiö JP, Rad ZJ, Sorokina SV, Punkkinen MPJ, Hedman HP, Punkkinen R, Laukkanen P, Kokko K. Atomic-Scale Modification of Oxidation Phenomena on the Ge(100) Surface by Si Alloying. ACS MATERIALS AU 2021; 2:204-214. [PMID: 36855760 PMCID: PMC9888653 DOI: 10.1021/acsmaterialsau.1c00039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Properties of Ge oxides are significantly different from those of widely used Si oxides. For example, the instability of GeO x at device junctions causes electronic defect levels that degrade the performance of Ge-containing devices (e.g., transistors and infrared detectors). Therefore, the passivating Si layers have been commonly used at Ge interfaces to reduce the effects of Ge oxide instability and mimic the successful strategy of Si oxidation. To contribute to the atomic-scale knowledge and control of oxidation of such Si-alloyed Ge interfaces (O/Si/Ge), we present a synchrotron radiation core-level study of O/Si/Ge, which is combined with scanning probe microscopy measurements. The oxidation processes and electronic properties of O/Si/Ge(100) are examined as functions of Si amount and oxidation doses. In particular, the incorporation of Si into Ge is shown to cause the strengthening of Ge-O bonds and the increase of incorporated oxygen amount in oxide/Ge junctions, supporting that the method is useful to decrease the defect-level densities.
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Affiliation(s)
- Mikhail Kuzmin
- Department
of Physics and Astronomy, University of
Turku, FI-20014 Turku, Finland,Ioffe
Institute, Russian Academy of Sciences, St. Petersburg 194021, Russian Federation,
| | - Juha-Pekka Lehtiö
- Department
of Physics and Astronomy, University of
Turku, FI-20014 Turku, Finland
| | - Zahra Jahanshah Rad
- Department
of Physics and Astronomy, University of
Turku, FI-20014 Turku, Finland
| | - Svetlana V. Sorokina
- Ioffe
Institute, Russian Academy of Sciences, St. Petersburg 194021, Russian Federation
| | | | - Hannu-Pekka Hedman
- Department
of Information Technology, University of
Turku, FI-20014 Turku, Finland
| | - Risto Punkkinen
- Department
of Information Technology, University of
Turku, FI-20014 Turku, Finland
| | - Pekka Laukkanen
- Department
of Physics and Astronomy, University of
Turku, FI-20014 Turku, Finland
| | - Kalevi Kokko
- Department
of Physics and Astronomy, University of
Turku, FI-20014 Turku, Finland
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3
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Shklyaev AA, Latyshev AV. Dewetting behavior of Ge layers on SiO 2 under annealing. Sci Rep 2020; 10:13759. [PMID: 32792554 PMCID: PMC7426840 DOI: 10.1038/s41598-020-70723-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 07/27/2020] [Indexed: 11/09/2022] Open
Abstract
The solid-state dewetting phenomenon in Ge layers on SiO2 is investigated as a function of layer thickness dGe (from 10 to 86 nm) and annealing temperature. The dewetting is initiated at about 580-700 °C, depending on dGe, through the appearance of surface undulation leading to the particle formation and the rupture of Ge layers by narrow channels or rounded holes in the layers with the thicknesses of 10-60 and 86 nm, respectively. The channel widths are significantly narrower than the distance between the particles that causes the formation of thinned Ge layer areas between particles at the middle dewetting stage. The thinned areas are then agglomerated into particles of smaller sizes, leading to the bimodal distributions of the Ge particles which are different in shape and size. The existence of a maximum in the particle pair correlation functions, along with the quadratic dependence of the corresponding particle spacing on dGe, may indicate the spinodal mechanism of the dewetting in the case of relatively thin Ge layers. Despite the fact that the particle shape, during the solid-state dewetting, is not thermodynamically equilibrium, the use of the Young's equation and contact angles allows us to estimate the particle/substrate interface energy.
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Affiliation(s)
- A A Shklyaev
- A.V. Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090, Russia.
| | - A V Latyshev
- A.V. Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk, 630090, Russia
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4
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Scappucci G, Klesse WM, Yeoh LA, Carter DJ, Warschkow O, Marks NA, Jaeger DL, Capellini G, Simmons MY, Hamilton AR. Bottom-up assembly of metallic germanium. Sci Rep 2015; 5:12948. [PMID: 26256239 PMCID: PMC4530340 DOI: 10.1038/srep12948] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/13/2015] [Indexed: 11/12/2022] Open
Abstract
Extending chip performance beyond current limits of miniaturisation requires new materials and functionalities that integrate well with the silicon platform. Germanium fits these requirements and has been proposed as a high-mobility channel material, a light emitting medium in silicon-integrated lasers, and a plasmonic conductor for bio-sensing. Common to these diverse applications is the need for homogeneous, high electron densities in three-dimensions (3D). Here we use a bottom-up approach to demonstrate the 3D assembly of atomically sharp doping profiles in germanium by a repeated stacking of two-dimensional (2D) high-density phosphorus layers. This produces high-density (1019 to 1020 cm−3) low-resistivity (10−4Ω · cm) metallic germanium of precisely defined thickness, beyond the capabilities of diffusion-based doping technologies. We demonstrate that free electrons from distinct 2D dopant layers coalesce into a homogeneous 3D conductor using anisotropic quantum interference measurements, atom probe tomography, and density functional theory.
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Affiliation(s)
- Giordano Scappucci
- School of Physics, University of New South Wales, Sydney, 2052, Australia
| | - Wolfgang M Klesse
- School of Physics, University of New South Wales, Sydney, 2052, Australia
| | - LaReine A Yeoh
- School of Physics, University of New South Wales, Sydney, 2052, Australia
| | - Damien J Carter
- 1] Department of Chemistry, Curtin University, Perth WA 6845, Australia. [2] Nanochemistry Research Institute, Curtin University, Perth WA 6845, Australia
| | - Oliver Warschkow
- Centre for Quantum Computation and Communication Technology, School of Physics, The University of Sydney, Sydney NSW 2006, Australia
| | - Nigel A Marks
- 1] Nanochemistry Research Institute, Curtin University, Perth WA 6845, Australia. [2] Department of Physics and Astronomy, Curtin University, Perth WA 6845, Australia
| | - David L Jaeger
- Department of Material Science and Engineering, University of North Texas, Denton, Texas 76209, United States
| | - Giovanni Capellini
- 1] IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany. [2] Dipartimento di Scienze, Università Roma Tre, Viale Marconi 446, 00146 Rome, Italy
| | - Michelle Y Simmons
- 1] School of Physics, University of New South Wales, Sydney, 2052, Australia. [2] Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
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5
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Persichetti L, Sgarlata A, Mori S, Notarianni M, Cherubini V, Fanfoni M, Motta N, Balzarotti A. Beneficial defects: exploiting the intrinsic polishing-induced wafer roughness for the catalyst-free growth of Ge in-plane nanowires. NANOSCALE RESEARCH LETTERS 2014; 9:358. [PMID: 25114649 PMCID: PMC4119939 DOI: 10.1186/1556-276x-9-358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 07/09/2014] [Indexed: 06/03/2023]
Abstract
UNLABELLED We outline a metal-free fabrication route of in-plane Ge nanowires on Ge(001) substrates. By positively exploiting the polishing-induced defects of standard-quality commercial Ge(001) wafers, micrometer-length wires are grown by physical vapor deposition in ultra-high-vacuum environment. The shape of the wires can be tailored by the epitaxial strain induced by subsequent Si deposition, determining a progressive transformation of the wires in SiGe faceted quantum dots. This shape transition is described by finite element simulations of continuous elasticity and gives hints on the equilibrium shape of nanocrystals in the presence of tensile epitaxial strain. PACS 81.07.Gf; 68.35.bg; 68.35.bj; 62.23.Eg.
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Affiliation(s)
- Luca Persichetti
- Department of Materials, ETH Zurich, Hönggerbergring 64, Zürich 8093, Switzerland
| | - Anna Sgarlata
- Dipartimento di Fisica, Università di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, Rome 0133, Italy
| | - Stefano Mori
- Dipartimento di Fisica, Università di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, Rome 0133, Italy
- Dipartimento di Ingegneria dell’Impresa, ‘Mario Lucertini’, via del Politecnico 1, Rome 00133, Italy
| | - Marco Notarianni
- Institute for Future Environments and School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Valeria Cherubini
- Dipartimento di Fisica, Università di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, Rome 0133, Italy
| | - Massimo Fanfoni
- Dipartimento di Fisica, Università di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, Rome 0133, Italy
| | - Nunzio Motta
- Institute for Future Environments and School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Adalberto Balzarotti
- Dipartimento di Fisica, Università di Roma ‘Tor Vergata’, Via della Ricerca Scientifica 1, Rome 0133, Italy
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Mattoni G, Klesse WM, Capellini G, Simmons MY, Scappucci G. Phosphorus molecules on Ge(001): a playground for controlled n-doping of germanium at high densities. ACS NANO 2013; 7:11310-11316. [PMID: 24224765 DOI: 10.1021/nn4051634] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The achievement of controlled high n-type doping in Ge will enable the fabrication of a number of innovative nanoelectronic and photonic devices. In this work, we present a combined scanning tunneling microscopy, secondary ions mass spectrometry, and magnetotransport study to understand the atomistic doping process of Ge by P2 molecules. Harnessing the one-dimer footprint of P2 molecules on the Ge(001) surface, we achieved the incorporation of a full P monolayer in Ge using a relatively low process temperature. The consequent formation of P-P dimers, however, limits electrical activation above a critical donor density corresponding to P-P spacing of less than a single dimer row. With this insight, tuning of doping parameters allows us to repeatedly stack such 2D P layers to achieve 3D electron densities up to ∼2 × 10(20) cm(-3).
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Affiliation(s)
- Giordano Mattoni
- School of Physics, University of New South Wales , Sydney, NSW 2052, Australia
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Scappucci G, Capellini G, Klesse WM, Simmons MY. New avenues to an old material: controlled nanoscale doping of germanium. NANOSCALE 2013; 5:2600-2615. [PMID: 23455600 DOI: 10.1039/c3nr34258a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review our recent research into n-type doping of Ge for nanoelectronics and integrated photonics. We demonstrate a doping method in ultra-high vacuum to achieve high electron concentrations in Ge while maintaining atomic-level control of the doping process. We integrated this doping technique with ultra-high vacuum scanning tunneling microscope lithography and femtosecond laser ablation micron-scale lithography, and demonstrated basic components of donor-based nanoelectronic circuitry such as wires and tunnel gaps. By repetition of controlled doping cycles we have shown that stacking of multiple Ge:P two-dimensional electron gases results in high electron densities in Ge (>10(20) cm(-3)). Because of the strong vertical electron confinement, closely stacked 2D layers - although interacting - maintain their individuality in terms of electron transport. These results bode well towards the realization of nanoscale 3D epitaxial circuits in Ge comprising stacked 2DEGs and/or atomic-scale Ge:P devices with confinement in more dimensions.
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Affiliation(s)
- Giordano Scappucci
- School of Physics, University of New South Wales, Sydney, NSW 2052, Australia.
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8
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Scappucci G, Warschkow O, Capellini G, Klesse WM, McKenzie DR, Simmons MY. n-type doping of germanium from phosphine: early stages resolved at the atomic level. PHYSICAL REVIEW LETTERS 2012; 109:076101. [PMID: 23006385 DOI: 10.1103/physrevlett.109.076101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Indexed: 06/01/2023]
Abstract
To understand the atomistic doping process of phosphorus in germanium, we present a combined scanning tunneling microscopy, temperature programed desorption, and density functional theory study of the reactions of phosphine with the Ge(001) surface. Combining experimental and theoretical results, we demonstrate that PH(2) + H with a footprint of one Ge dimer is the only product of room temperature chemisorption. Further dissociation requires thermal activation. At saturation coverage, PH(2) + H species self-assemble into ordered patterns leading to phosphorus coverages of up to 0.5 monolayers.
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Affiliation(s)
- G Scappucci
- School of Physics, University of New South Wales, Sydney, Australia.
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