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Wu Y, Zhou P, Xiao Y, Sun K, Wang D, Wang P, Mi Z. Achieving atomically ordered GaN/AlN quantum heterostructures: The role of surface polarity. Proc Natl Acad Sci U S A 2023; 120:e2303473120. [PMID: 37874860 PMCID: PMC10622873 DOI: 10.1073/pnas.2303473120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 09/19/2023] [Indexed: 10/26/2023] Open
Abstract
Interface engineering in heterostructures at the atomic scale has been a central research focus of nanoscale and quantum material science. Despite its paramount importance, the achievement of atomically ordered heterointerfaces has been severely limited by the strong diffusive feature of interfacial atoms in heterostructures. In this work, we first report a strong dependence of interfacial diffusion on the surface polarity. Near-perfect quantum interfaces can be readily synthesized on the semipolar plane instead of the conventional c-plane of GaN/AlN heterostructures. The chemical bonding configurations on the semipolar plane can significantly suppress the cation substitution process as evidenced by first-principles calculations, which leads to an atomically sharp interface. Moreover, the surface polarity of GaN/AlN can be readily controlled by varying the strain relaxation process in core-shell nanostructures. The obtained extremely confined, interdiffusion-free ultrathin GaN quantum wells exhibit a high internal quantum efficiency of ~75%. Deep ultraviolet light-emitting diodes are fabricated utilizing a scalable and robust method and the electroluminescence emission is nearly free of the quantum-confined Stark effect, which is significant for ultrastable device operation. The presented work shows a vital path for achieving atomically ordered quantum heterostructures for III-nitrides as well as other polar materials such as III-arsenides, perovskites, etc.
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Affiliation(s)
- Yuanpeng Wu
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
| | - Peng Zhou
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
| | - Yixin Xiao
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
| | - Kai Sun
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI48109
| | - Ding Wang
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
| | - Ping Wang
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
| | - Zetian Mi
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI48109
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2
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Periša I, Tkalčević M, Isaković S, Basioli L, Ivanda M, Bernstorff S, Mičetić M. Ge/Al and Ge/Si 3N 4/Al Core/Shell Quantum Dot Lattices in Alumina: Boosting the Spectral Response by Tensile Strain. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6211. [PMID: 36143521 PMCID: PMC9505235 DOI: 10.3390/ma15186211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 06/16/2023]
Abstract
We investigated the production conditions and optoelectrical properties of thin film material consisting of regularly ordered core/shell Ge/Al and Ge/Si3N4/Al quantum dots (QDs) in an alumina matrix. The materials were produced by self-assembled growth achieved by means of multilayer magnetron sputtering deposition. We demonstrated the successful fabrication of well-ordered 3D lattices of Ge/Al and Ge/Si3N4/Al core/shell quantum dots with a body-centred tetragonal arrangement within the Al2O3 matrix. The addition of shells to the Ge core enables a strong tuning of the optical and electrical properties of the material. An Al shell induces a bandgap shift toward smaller energies, and, in addition, it prevents Ge oxidation. The addition of a thin Si3N4 shell induces huge changes in the material spectral response, i.e., in the number of extracted excitons produced by a single photon. It increases both the absolute value and the width of the spectral response. For the best sample, we achieved an enhancement of over 250% of the produced number of excitons in the measured energy range. The observed changes are, as it seems, the consequence of the large tensile strain in Ge QDs which is induced by the Si3N4 shell addition and which is measured to be about 3% for the most strained QDs. The tensile strain causes activation of the direct bandgap of germanium, which has a very strong effect on the spectral response of the material.
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Affiliation(s)
- Ivana Periša
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Marija Tkalčević
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Senad Isaković
- Faculty of Science, University of Sarajevo, Zmaja od Bosne 33–35, 71000 Sarajevo, Bosnia and Herzegovina
| | - Lovro Basioli
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Mile Ivanda
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Sigrid Bernstorff
- Elettra Sincrotrone, S.C.p.A., Strada Statale 14, km 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
| | - Maja Mičetić
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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3
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Multiple Exciton Generation in 3D-Ordered Networks of Ge Quantum Wires in Alumina Matrix. MATERIALS 2022; 15:ma15155353. [PMID: 35955285 PMCID: PMC9369923 DOI: 10.3390/ma15155353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/14/2022] [Accepted: 07/28/2022] [Indexed: 12/10/2022]
Abstract
Thin films containing 3D-ordered semiconductor quantum wires offer a great tool to improve the properties of photosensitive devices. In the present work, we investigate the photo-generated current in thin films consisting of an interconnected 3D-ordered network of Ge quantum wires in an alumina matrix. The films are prepared using nitrogen-assisted magnetron sputtering co-deposition of Ge and Al2O3. We demonstrate a strong photocurrent generation in the films, much stronger than in similar films containing Ge quantum dots. The enhanced photocurrent generation is the consequence of the multiple exciton generation and the films’ specific structure that allows for efficient carrier transport. Thin film with the largest nitrogen content showed enhanced performance compared to other thin films with 1.6 excitons created after absorption of a single photon at an energy nearly equal to the double bandgap value. The bandgap value depends on the geometrical properties of the quantum wires, and it is close to the maximum of the solar irradiance in this case. In addition, we show that the multiple exciton generation is the most pronounced at the photon energy values equal to multiple values of the thin film bandgap.
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Bartmann MG, Sistani M, Glassner S, Salem B, Baron T, Gentile P, Smoliner J, Lugstein A. Verifying the band gap narrowing in tensile strained Ge nanowires by electrical means. NANOTECHNOLOGY 2021; 32:145711. [PMID: 33276352 DOI: 10.1088/1361-6528/abd0b2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Group-IV based light sources are one of the missing links towards fully CMOS compatible photonic circuits. Combining both silicon process compatibility and a pseudo-direct band gap, germanium is one of the most viable candidates. To overcome the limitation of the indirect band gap and turning germanium in an efficient light emitting material, the application of strain has been proven as a promising approach. So far the experimental verification of strain induced bandgap modifications were based on optical measurements and restricted to moderate strain levels. In this work, we demonstrate a methodology enabling to apply tunable tensile strain to intrinsic germanium [Formula: see text] nanowires and simultaneously perform in situ optical as well as electrical characterization. Combining I/V measurements and μ-Raman spectroscopy at various strain levels, we determined a decrease of the resistivity by almost three orders of magnitude for strain levels of ∼5%. Thereof, we calculated the strain induced band gap narrowing in remarkable accordance to recently published simulation results for moderate strain levels up to 3.6%. Deviations for ultrahigh strain values are discussed with respect to surface reconfiguration and reduced charge carrier scattering time.
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Affiliation(s)
- M G Bartmann
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, A-1040 Vienna, Austria
| | - M Sistani
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, A-1040 Vienna, Austria
| | - S Glassner
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, A-1040 Vienna, Austria
| | - B Salem
- Univ. Grenoble Alpes, CNRS, CEA/Leti Minatec, Grenoble INP, LTM, F-38054 Grenoble, France
| | - T Baron
- Univ. Grenoble Alpes, CNRS, CEA/Leti Minatec, Grenoble INP, LTM, F-38054 Grenoble, France
| | - P Gentile
- Univ. Grenoble Alpes, CEA, IRIG- PHELIQS, F-38054 Grenoble, France
| | - J Smoliner
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, A-1040 Vienna, Austria
| | - A Lugstein
- Institute of Solid State Electronics, Technische Universität Wien, Gußhausstraße 25-25a, A-1040 Vienna, Austria
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Pura JL, Periwal P, Baron T, Jiménez J. Growth dynamics of SiGe nanowires by the vapour-liquid-solid method and its impact on SiGe/Si axial heterojunction abruptness. NANOTECHNOLOGY 2018; 29:355602. [PMID: 29869997 DOI: 10.1088/1361-6528/aaca74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The vapour-liquid-solid (VLS) method is by far the most extended procedure for bottom-up nanowire growth. This method also allows for the manufacture of nanowire axial heterojunctions in a straightforward way. To do this, during the growth process, precursor gases are switched on/off to obtain the desired change in the nanowire composition. Using this technique, axially heterostructured nanowires can be grown, which are crucial for the fabrication of electronic and optoelectronic devices. SiGe/Si nanowires are compatible with complementary metal oxide semiconductor (CMOS) technology, which improves their versatility and the possibility of integration with current electronic technologies. Abrupt heterointerfaces are fundamental for the development and correct operation of electronic and optoelectronic devices. Unfortunately, the VLS growth of SiGe/Si heterojunctions does not provide abrupt transitions because of the high solubility of group IV semiconductors in Au, with the corresponding reservoir effect that precludes the growth of sharp interfaces. In this work, we studied the growth dynamics of SiGe/Si heterojunctions based on already developed models for VLS growth. A composition map of the Si-Ge-Au liquid alloy is proposed to better understand the impact of the growing conditions on the nanowire growth process and the heterojunction formation. The solution of our model provides heterojunction profiles that are in good agreement with the experimental measurements. Finally, an in-depth study of the composition map provides a practical approach to the drastic reduction of heterojunction abruptness by reducing the Si and Ge concentrations in the catalyst droplet. This converges with previous approaches, which use catalysts aiming to reduce the solubility of the atomic species. This analysis opens new paths to the reduction of heterojunction abruptness using Au catalysts, but the model can be naturally extended to other catalysts and semiconductors.
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Affiliation(s)
- J L Pura
- GdS Optronlab, Dpt. Física de la Materia Condensada, ed. LUCIA Universidad de Valladolid, Paseo de Belén 19, E-47011 Valladolid, Spain
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Gu T, Gao J, Ostroumov EE, Jeong H, Wu F, Fardel R, Yao N, Priestley RD, Scholes GD, Loo YL, Arnold CB. Photoluminescence of Functionalized Germanium Nanocrystals Embedded in Arsenic Sulfide Glass. ACS APPLIED MATERIALS & INTERFACES 2017; 9:18911-18917. [PMID: 28485911 DOI: 10.1021/acsami.7b02520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Embedding metallic and semiconductor nanoparticles in a chalcogenide glass matrix effectively modifies the photonic properties. Such nanostructured materials could play an important role in optoelectronic devices, catalysis, and imaging applications. In this work, we fabricate and characterize germanium nanocrystals (Ge NCs) embedded in arsenic sulfide thin films by pulsed laser ablation in aliphatic amine solutions. Unstable surface termination of aliphatic groups and stable termination by amine on Ge NCs are indicated by Raman and Fourier-transform infrared spectroscopy measurements. A broad-band photoluminescence in the visible range is observed for the amine functionalized Ge NCs. A noticeable enhancement of fluorescence is observed for Ge NCs in arsenic sulfide, after annealing to remove the residual solvent of the glass matrix.
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Affiliation(s)
- Tingyi Gu
- Electrical and Computer Engineering, University of Delaware , Newark, Delaware 19716, United States
| | - Jia Gao
- Department of Chemical and Biological Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | - Evgeny E Ostroumov
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
| | - Hyuncheol Jeong
- Department of Chemical and Biological Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | - Fan Wu
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Romain Fardel
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
| | - Nan Yao
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Rodney D Priestley
- Department of Chemical and Biological Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Gregory D Scholes
- Department of Chemistry, Princeton University , Princeton, New Jersey 08544, United States
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University , Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University , Princeton, New Jersey 08544, United States
| | - Craig B Arnold
- Princeton Institute for the Science and Technology of Materials, Princeton University , Princeton, New Jersey 08544, United States
- Department of Mechanical and Aerospace Engineering, Princeton University , Princeton, New Jersey 08544, United States
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McLeod JA, Zhao J, Yang L, Liu Y, Liu L. Structural evolution of reduced GeO x nanoparticles. Phys Chem Chem Phys 2017; 19:3182-3191. [PMID: 28083591 DOI: 10.1039/c6cp07354a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
GeOx nanoparticles (NPs) are of growing interest in lithium storage and optoelectronics. GeOx NPs prepared by chemical reduction, exposed to air or retained under N2, then annealed under H2 at various temperatures are studied herein using soft X-ray spectroscopy. We find that fresh and air-exposed GeOx NPs evolve rather differently under annealing. The fresh GeOx NPs start as a very amorphous heterogeneous mixture of GeOx and Ge, and during annealing both the valence band and conduction band edges evolve. In contrast, the air-exposed GeOx NPs initially contain quartz-phase GeO2, and during annealing only the conduction band edge evolves due to increased oxygen vacancies forming unoccupied defect states (the valence band does not change until annealing at high temperture, at which point almost all of the GeO2 is removed). These findings suggest a preparation and annealing strategy that could be used to tailor GeOx NPs for their intended use in lithium storage or optoelectronic applications.
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Affiliation(s)
- John A McLeod
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
| | - Jia Zhao
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
| | - Linju Yang
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
| | - Yi Liu
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
| | - Lijia Liu
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, China.
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Cosentino S, Torrisi G, Raciti R, Zimbone M, Crupi I, Mirabella S, Terrasi A. Growth kinetics of colloidal Ge nanocrystals for light harvesters. RSC Adv 2016. [DOI: 10.1039/c6ra03490j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Representation of growth kinetics mechanisms that strongly control synthesis and final dimension of colloidal nanocrystals.
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Affiliation(s)
- Salvatore Cosentino
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
- Laboratory of Solid State Physics and Magnetism
| | - Giacomo Torrisi
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
| | - Rosario Raciti
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
| | - Massimo Zimbone
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
| | - Isodiana Crupi
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
- Department of Energy
| | - Salvo Mirabella
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
| | - Antonio Terrasi
- CNR-IMM and Dipartimento di Fisica e Astronomia
- Università di Catania
- Catania
- Italy
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