Band Structure of Strain-Balanced GaAsBi/GaAsN Super-lattices on GaAs
- Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Electrical Engineering and Computer Science
GaAs alloys with dilute content of Bi and N provide a large reduction in band-gap energy with increasing alloy composition. GaAsBi/GaAsN heterojunctions have a type-II band alignment, where superlattices based on these materials offer a wide range for designing effective band-gap energy by varying superlattice period and alloy composition. The miniband structure and effective band gap for strain-balanced GaAsBi/GaAsN superlattices with effective lattice match to GaAs are calculated for alloy compositions up to 5% Bi and N using the k·p method. The effective band gap for these superlattices is found to vary between 0.89 and 1.32 eV for period thickness ranging from 10 to 100 Å. The joint density of states and optical absorption of a 40/40 Å GaAs0.96Bi0.04/GaAs0.98N0.02 superlattice are reported demonstrating a ground-state transition at 1.005 eV and first excited transition at 1.074 eV. The joint density of states is similar in magnitude to GaAs, while the optical absorption is approximately one order of magnitude lower due to the spatially indirect optical transition in the type-II structure. The GaAsBi/GaAsN system may provide a new material system with lattice match to GaAs in a spectral range of high importance for optoelectronic devices including solar cells, photodetectors, and light emitters.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Solar and Thermal Energy Conversion (CSTEC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC0000957
- OSTI ID:
- 1065554
- Journal Information:
- Phys. Rev. B, Vol. 83, Issue 19; Related Information: CSTEC partners with University of Michigan (lead); Kent State University; ISSN 1098-0121: PRBMDO
- Publisher:
- American Physical Society (APS)
- Country of Publication:
- United States
- Language:
- English
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