Characterization of recombination processes in epitaxial thin films and substrates for antimonide based thermophotovoltaic devices [electronic resource]
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| Online Access: |
Online Access |
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| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, DC : Oak Ridge, Tenn. :
United States. Office of the Assistant Secretary for Nuclear Energy ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy,
1998.
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| Abstract: | Recombination processes in antimonide-based materials for thermophotovoltaic (TPV) devices have been investigated using a radio-frequency (RF) photoreflectance technique, in which a Nd-YAG pulsed laser is used to excite excess carriers, and the short-pulse response and photoconductivity decay are monitored with an inductively-coupled non-contacting RF probe. Double-capped lattice-matched GaInAsSb organometallic vapor phase epitaxy (OMVPE)--grown layers on GaSb substrates have been used to evaluate bulk lifetime and surface recombination velocity with different layer thicknesses. With an active layer doping of 2 {times} 10¹⁷ cm⁻³, effective bulk lifetimes of 95 ns and surface recombination velocities of 1,900 cm/s have been obtained. As the laser intensity is increased the lifetime decreases, which may be indicative of radiative recombination under these high level injection conditions. Similar measurements have been taken on both commercially available GaSb boules as well as in-house grown quaternary GaInAsSb boules. A two-step decay is observed with the quaternary boules, an initial decay of nominally 15 ns which is relatively independent of laser intensity and a second decay of 30--60 ns which increases with decreasing laser intensity. This behavior may be indicative of free charge separation as a result of short-range ordering in the quaternary crystals. GaSb boules, both commercially available and those grown in-house, exhibit more classical characteristics. |
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| Item Description: | Published through the Information Bridge: DOE Scientific and Technical Information. 06/01/1998. "KAPL-P--000098" "K--98107;CONF-9806176--" "DE99001634" 40. electronic materials conference, Charlottesville, VA (United States), 24 Jun 1998. Wang, C.; Dutta, P.; Charache, G.; Gutmann, R.; Borrego, J.; Ostrogorsky, A.; Saroop, S. Knolls Atomic Power Lab., Schenectady, NY (United States) |
| Physical Description: | 14 p. |