Impact of extended defects on recombination in CdTe heterostructures grown by molecular beam epitaxy
- Colorado State Univ., Fort Collins, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Texas State Univ., San Marcos, TX (United States)
Heterostructures with CdTe and CdTe1-xSex (x ~ 0.01) absorbers between two wider-band-gap Cd1-xMgxTe barriers (x ~ 0.25–0.3) were grown by molecular beam epitaxy to study carrier generation and recombination in bulk materials with passivated interfaces. Using a combination of confocal photoluminescence (PL), time-resolved PL, and low-temperature PL emission spectroscopy, two extended defect types were identified and the impact of these defects on charge-carrier recombination was analyzed. Here, the dominant defects identified by confocal PL were dislocations in samples grown on (211)B CdTe substrates and crystallographic twinning-related defects in samples on (100)-oriented InSb substrates. Low-temperature PL shows that twin-related defects have a zero-phonon energy of 1.460 eV and a Huang-Rhys factor of 1.50, while dislocation-dominated samples have a 1.473-eV zero-phonon energy and a Huang-Rhys factor of 1.22. The charge carrier diffusion length near both types of defects is ~6 μm, suggesting that recombination is limited by diffusion dynamics. For heterostructures with a low concentration of extended defects, the bulk lifetime was determined to be 2.2 μs with an interface recombination velocity of 160 cm/s and an estimated radiative lifetime of 91 μs.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Grant/Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1326171
- Alternate ID(s):
- OSTI ID: 1312053
- Report Number(s):
- NREL/JA-5K00-67149; APPLAB
- Journal Information:
- Applied Physics Letters, Vol. 109, Issue 9; ISSN 0003-6951
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Structural and electronic properties of CdTe 1-x Se x films and their application in solar cells
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journal | August 2018 |
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Related Subjects
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
photoluminescence
epitaxy
II-VI semiconductors
diffusion
III-V semiconductors
emission spectroscopy
semiconductors
lasers
electronic devices
charge recombination
time-resolved photoluminescence
atomic force microscopy
heterostructures
phonons