Al[sub x]Ga[sub 1[minus]x]Sb window layers for InGaAsSb/GaSb thermophotovoltaic cells
- Materials Science and Engineering, University of Delaware, Newark, Delaware 19716-2000 (United States)
We report results of a comparative study of AlSb-based window layers for InGaAsSb/GaSb TPV cells made by liquid-phase epitaxy (LPE). Previous work has shown that an AlGaAsSb window layer significantly improves the performance of InGaAsSb/GaSb TPV cells. As expected, the window layer enhances short-wavelength spectral response and increases the open-circuit voltage by reducing the reverse-saturation current of the diode. We present results for a simpler alternative window layer based on the ternary AlGaSb alloy. We fabricated, characterized, and compared InGaAsAsSb TPV of three types: 1. with an AlGaAsSb window layer, 2. with an AlAsSb window layer, and 3. with no window layer. Both [ital p]-on-[ital n] ([ital p]-type InGaAsSb emitter; [ital n]-type InGaAsSb base) and [ital n]-on-[ital p] ([ital n]-type InGaAsSb emitter; [ital p]-type InGaAsSb base) homojunction cell configurations were investigated. The InGaAsSb layers have a [approximately]0.55-ev bandgap and are lattice-matched to a GaSb substrate. As anticipated, both AlGaSb and AlGaAsSb passivated TPV cells were superior to cells without a window layer. The AlGaAsSb/InGaAsSb window/emitter interface is closely lattice matched and would be expected to provide better surface passivation than AlGaSb/InGaAsSb window/emitter interface which has a 0.6[percent] lattice mismatch. On the contrary, our experimental results showed that, based on a comparison of spectral response, AlGaSb window layers were somewhat more effective than AlGaAsSb in passivating the front surface of InGaAsSb diodes. These results demonstrate the viability of a simpler ternary AlGaSb alloy as an alternative to the quaternary AlGaAsSb alloy as a window layer material. [copyright] [ital 1999 American Institute of Physics.]
- DOE Contract Number:
- FG02-97ER86057
- OSTI ID:
- 6097142
- Report Number(s):
- CONF-981055--
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Vol. 460:1; ISSN 0094-243X; ISSN APCPCS
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
140600 -- Solar Energy-- Photovoltaic Power Systems
ALLOY SYSTEMS
ALUMINIUM COMPOUNDS
ANTIMONIDES
ANTIMONY COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CONVERSION
DIRECT ENERGY CONVERSION
DIRECT ENERGY CONVERTERS
EMISSIVITY
ENERGY CONVERSION
FABRICATION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INDIUM ANTIMONIDES
INDIUM COMPOUNDS
LATTICE PARAMETERS
OPTICAL PROPERTIES
PASSIVATION
PERFORMANCE
PHYSICAL PROPERTIES
PNICTIDES
QUATERNARY ALLOY SYSTEMS
SPECTRAL RESPONSE
SURFACE PROPERTIES
TERNARY ALLOY SYSTEMS
THERMOPHOTOVOLTAIC CONVERTERS