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23 April 2001 Control of low-temperature-grown GaAs for ultrafast switching applications
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Proceedings Volume 4280, Ultrafast Phenomena in Semiconductors V; (2001)
Event: Symposium on Integrated Optics, 2001, San Jose, CA, United States
The dynamic properties of low-temperature-grown GaAs (LT- GaAs) depend critically on growth and annealing conditions, such as substrate temperature during the MBE process (Ts), annealing temperature (Ta) and duration ((tau) a). Previous empirical models based on carrier rate- equations introduce parameters, such as carrier lifetime, that cannot be directly correlated with growth and annealing conditions. The Schockley-Read-Hall model we use here introduces deep donor (NDD) and acceptor (NA) concentrations, instead of lifetimes. In LT-GaAs, deep donors are in majority constituted by an As-antisite related defect. The acceptors, in absence of doping, are most likely constituted either by Ga vacancy defects or by the residual doping during MBE growth. The samples studied are grown on GaAs semi-insulating substrates at different Ts and annealed under different conditions. For each sample, we first measure NDD using X-ray diffraction analysis. Then we fit both continuous photoconductivity and pump-probe reflectometry measurements using NA as the only adjustable parameter. From the set of data obtained, we can relate Ts, Ta and (tau) a with NDD and NA. This gives us a way to predict LT-GaAs dynamics from growth and annealing continues. This approach has been used to fabricate ultrafast photoconductive switches showing high sensitivity and good insulation.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Valentin Ortiz, Max Stellmacher, Xavier Marcadet, Stephane Formont, Didier Adam, Julien Nagle, Jean-Francois Lampin, and Antigoni Alexandrou "Control of low-temperature-grown GaAs for ultrafast switching applications", Proc. SPIE 4280, Ultrafast Phenomena in Semiconductors V, (23 April 2001);

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