Time-Resolved Transient Grating Spectroscopy for Studies of Nonequilibrium Carrier Dynamics in Wide Band-Gap Semiconductors
K. Jarašiūnas, T. Malinauskas, K. Neimontas, V. Gudelis and R. Aleksiejūnas
Department of Semiconductor Optoelectronics, Institute of Materials Science and Applied Research, Vilnius University, Saulėtekio Ave. 9-III, 10222 Vilnius, Lithuania
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Received: 17 06 2006;
Using interdisciplinary fields relevant to a highly excited semiconductor - nonequilibrium phenomena in high density plasma, light-induced changes of optical properties, and dynamic holography, we developed time-resolved four-wave mixing technique for monitoring the spatial and temporal carrier dynamics in wide band-gap semiconductors. This opened a new possibility to analyse fast electronic processes in a non-destructive "all-optical" way, i.e. without any electrical contacts. This technique allowed evaluation of recombination and transport processes and the determination of important carrier parameters which directly reveal the material quality: carrier lifetime, bipolar diffusion coefficients, surface recombination rate, nonlinear recombination rate, diffusion length, threshold of stimulated recombination. The recent experimental studies of differently grown group III-nitrides (heterostructures and free standing films) as well silicon carbide epilayers by nondegenerate picosecond four-wave mixing are presented.
DOI: 10.12693/APhysPolA.110.201
PACS numbers: 72.20.Jv, 78.47.+p, 78.55.Cr