1
|
Fricker D, Atkinson P, Jin X, Lepsa M, Zeng Z, Kovács A, Kibkalo L, Dunin-Borkowski RE, Kardynał BE. Effect of surface gallium termination on the formation and emission energy of an InGaAs wetting layer during the growth of InGaAs quantum dots by droplet epitaxy. NANOTECHNOLOGY 2023; 34:145601. [PMID: 36595322 DOI: 10.1088/1361-6528/acabd1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 12/14/2022] [Indexed: 06/17/2023]
Abstract
Self-assembled quantum dots (QDs) based on III-V semiconductors have excellent properties for applications in quantum optics. However, the presence of a 2D wetting layer (WL) which forms during the Stranski-Krastanov growth of QDs can limit their performance. Here, we investigate WL formation during QD growth by the droplet epitaxy technique. We use a combination of photoluminescence excitation spectroscopy, lifetime measurements, and transmission electron microscopy to identify the presence of an InGaAs WL in these droplet epitaxy QDs, even in the absence of distinguishable WL luminescence. We observe that increasing the amount of Ga deposited on a GaAs (100) surface prior to the growth of InGaAs QDs leads to a significant reduction in the emission wavelength of the WL to the point where it can no longer be distinguished from the GaAs acceptor peak emission in photoluminescence measurements. However increasing the amount of Ga deposited does not suppress the formation of a WL under the growth conditions used here.
Collapse
Affiliation(s)
- D Fricker
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - P Atkinson
- Institut des Nano Sciences de Paris, CNRS UMR 7588, Sorbonne Université, F-75005 Paris, France
| | - X Jin
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - M Lepsa
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Peter Grünberg Institute 10, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | - Z Zeng
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| | - A Kovács
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - L Kibkalo
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - R E Dunin-Borkowski
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute 5, Forschungszentrum Jülich, D-52428 Jülich, Germany
| | - B E Kardynał
- Peter Grünberg Institute 9, Forschungszentrum Jülich, D-52425 Jülich, Germany
- Department of Physics, RWTH Aachen University, D-52074 Aachen, Germany
| |
Collapse
|
2
|
Planck's generalised radiation law and its implications for cathodoluminescence spectra. Ultramicroscopy 2019; 204:73-80. [PMID: 31129495 DOI: 10.1016/j.ultramic.2019.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/09/2019] [Accepted: 05/19/2019] [Indexed: 11/24/2022]
Abstract
Cathodoluminescence (CL) is an important analytical technique for probing the optical properties of materials at high spatial resolution. Interpretation of CL spectra is however complicated by the fact that the spectrum depends on the carrier injection density of the incident electron beam. Here a generalised version of Planck's radiation law is used to uncover the evolution of CL spectra with injection under steady-state conditions. The importance of the quasi-Fermi level is highlighted and it is shown that steady-state luminescence is suppressed when the carrier distributions undergo a population inversion. The theory is consistent with some well-known luminescence phenomena, such as the blue shifting of donor-acceptor pair transitions with increased injection, and its predictions are experimentally verified on CdTe and GaN, which are exemplar thin-film solar cell and light emitting diode materials respectively. Furthermore, the discussion is broadened to include pulsed illumination in time resolved CL, where the carrier distribution is dynamically evolving with time.
Collapse
|
3
|
Mendis BG, Gachet D, Major JD, Durose K. Long Lifetime Hole Traps at Grain Boundaries in CdTe Thin-Film Photovoltaics. PHYSICAL REVIEW LETTERS 2015; 115:218701. [PMID: 26636877 DOI: 10.1103/physrevlett.115.218701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Indexed: 06/05/2023]
Abstract
A novel time-resolved cathodoluminescence method, where a pulsed electron beam is generated via the photoelectric effect, is used to probe individual CdTe grain boundaries. Excitons have a short lifetime (≤100 ps) within the grains and are rapidly quenched at the grain boundary. However, a ~47 meV shallow acceptor, believed to be due to oxygen, can act as a long lifetime hole trap, even at the grain boundaries where their concentration is higher. This provides direct evidence supporting recent observations of hopping conduction across grain boundaries in highly doped CdTe at low temperature.
Collapse
Affiliation(s)
- B G Mendis
- Deptartment of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - D Gachet
- Attolight AG, EPFL Innovation Square, Building D, 1015 Lausanne, Switzerland
| | - J D Major
- Stephenson Institute for Renewable Energy, University of Liverpool, Chadwick Building, Liverpool L69 7ZF, United Kingdom
| | - K Durose
- Stephenson Institute for Renewable Energy, University of Liverpool, Chadwick Building, Liverpool L69 7ZF, United Kingdom
| |
Collapse
|
4
|
Prospects for electron microscopy characterisation of solar cells: opportunities and challenges. Ultramicroscopy 2012; 119:82-96. [PMID: 22209471 DOI: 10.1016/j.ultramic.2011.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 09/08/2011] [Indexed: 11/22/2022]
Abstract
Several electron microscopy techniques available for characterising thin-film solar cells are described, including recent advances in instrumentation, such as aberration-correction, monochromators, time-resolved cathodoluminescence and focused ion-beam microscopy. Two generic problems in thin-film solar cell characterisation, namely electrical activity of grain boundaries and 3D morphology of excitionic solar cells, are also discussed from the standpoint of electron microscopy. The opportunities as well as challenges facing application of these techniques to thin-film and excitonic solar cells are highlighted.
Collapse
|
5
|
Reggiani L, Mitin V. Recombination and ionization processes at impurity centres in hot-electron semiconductor transport. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/bf02740011] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
6
|
Parish CM, Russell PE. Scanning Cathodoluminescence Microscopy. ADVANCES IN IMAGING AND ELECTRON PHYSICS 2007. [DOI: 10.1016/s1076-5670(07)47001-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
7
|
Bimberg D, Mycielski J. The recombination-induced temperature change of non-equilibrium charge carriers. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/19/13/020] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
9
|
Kozhevnikov M, Ashkinadze BM, Cohen E, Ron A. Self-oscillations at photoinduced impurity breakdown in GaAs. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:4855-4863. [PMID: 9981669 DOI: 10.1103/physrevb.52.4855] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
10
|
Dreybrodt J, Daiminger F, Reithmaier JP, Forchel A. Dynamics of carrier-capture processes in GaxIn1-xAs/GaAs near-surface quantum wells. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 51:4657-4660. [PMID: 9979319 DOI: 10.1103/physrevb.51.4657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
11
|
Woerner M, Lohner A, Elsaesser T, Kaiser W. Capture of hot holes by shallow acceptors in p-type GaAs studied by picosecond infrared spectroscopy. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:12498-12509. [PMID: 10005442 DOI: 10.1103/physrevb.47.12498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
13
|
Lohner A, Woerner M, Elsaesser T, Kaiser W. Picosecond capture of photoexcited holes by shallow acceptors in p-type GaAs. PHYSICAL REVIEW LETTERS 1992; 68:3920-3923. [PMID: 10045838 DOI: 10.1103/physrevlett.68.3920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
|
14
|
Grundmann M, Bimberg D, Fischer-Colbrie A, Miller JN. Recombination dynamics in pseudomorphic and partially relaxed In0.23Ga0.77As/GaAs quantum wells. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:10120-10123. [PMID: 9993395 DOI: 10.1103/physrevb.41.10120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
|
16
|
Dawes JM, Sceats MG. Electron trapping in quantum-well structures. PHYSICAL REVIEW. B, CONDENSED MATTER 1987; 36:9604-9611. [PMID: 9942857 DOI: 10.1103/physrevb.36.9604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
|