Projects per year
Abstract
The optical absorption coefficient is one of the fundamental properties of semiconductors and is critical to the development of optical devices. Herein, a revival of the constant photocurrent method is presented to measure sub-bandgap absorption in wide bandgap semiconductor films. The method involves maintaining a constant photocurrent by continually adjusting the impinging photon flux across the energy spectrum. Under such conditions, the reciprocal of the photon flux for uniformly absorbed light is proportional to the absorption coefficient. This method is applied to α-Ga 2O 3 and reveals that it can access the absorption coefficient from 1 × 10 5 cm −1 at the band edge (5.3 eV) to 0.8 cm −1 close to mid-bandgap (2.7 eV). Changes in the steepness of the absorption curve in the sub-bandgap region are in excellent agreement with defect states of α-Ga 2O 3 reported by deep level transient spectroscopy, indicating that the technique shows promise as a probe of energetically distributed defect states in thin film wide bandgap semiconductors.
Original language | English |
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Article number | 2300470 |
Number of pages | 7 |
Journal | Physica Status Solidi B |
Volume | 261 |
Issue number | 5 |
Early online date | 27 Feb 2024 |
DOIs | |
Publication status | Published - 1 May 2024 |
Funding
The authors acknowledge the support from the Royal Society (grant no. RGS/R1/201236) and the Engineering and Physical Sciences Research Council (grant nos. EP/T517938/1 and EP/V034995/1).
Keywords
- optical adsorption
- semiconductor films
- optical devices
- UV photodetectors
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Dive into the research topics of 'Constant photocurrent method to probe the sub-bandgap absorption in wide bandgap semiconductor films: the case of α-Ga2O3'. Together they form a unique fingerprint.Projects
- 2 Finished
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EPSRC Capital Award for Core Equipment grant: EP/V034995/1 (£52k)
Roberts, J. (Principal Investigator), Stillings, M. (Co-investigator), Knapp, M. (Co-investigator) & Lunn, R. (Co-investigator)
14/11/20 → 31/03/23
Project: Internally funded project
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Doctoral Training Partnership 2020-2021 University of Strathclyde | Nicol, David
Massabuau, F. (Principal Investigator), Martin, R. (Co-investigator) & Nicol, D. (Research Co-investigator)
EPSRC (Engineering and Physical Sciences Research Council)
1/10/20 → 1/02/24
Project: Research Studentship - Internally Allocated
Datasets
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Data for "Constant photocurrent method to probe the sub-bandgap absorption in wide bandgap semiconductor films: the case of α-Ga2O3"
Nicol, D. (Creator), Reynolds, S. (Creator), Roberts, J. (Creator), Jarman, J. (Creator), Chalker, P. (Creator) & Massabuau, F. (Creator), University of Strathclyde, 28 Feb 2024
DOI: 10.15129/6e23e883-8da6-49f0-aa15-4875e4c98f21
Dataset