Characterization of recombination processes in epitaxial thin films and substrates for antimonide based thermophotovoltaic devices
- Rensselaer Polytechnic Inst., Troy, NY (United States). Center for Integrated Electronics and Electronics Manufacturing
- Lockheed Martin Inc., Schenectady, NY (United States)
- Massachusetts Inst. of Tech., Lexington, MA (United States). Lincoln Lab.
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} 10{sup 17} cm{sup {minus}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.
- Research Organization:
- Knolls Atomic Power Lab. (KAPL), Niskayuna, NY (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Nuclear Energy, Washington, DC (United States)
- DOE Contract Number:
- AC12-76SN00052
- OSTI ID:
- 307874
- Report Number(s):
- KAPL-P-000098; K-98107; CONF-9806176-; ON: DE99001634; TRN: AHC29905%%51
- Resource Relation:
- Conference: 40. electronic materials conference, Charlottesville, VA (United States), 24 Jun 1998; Other Information: PBD: Jun 1998
- Country of Publication:
- United States
- Language:
- English
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