Carrier transport and recombination in InGaN/GaN heterostructures, studied by optical four‐wave mixing technique

Time-resolved four-wave mixing has been performed in InGaN/GaN/sapphire heterostructures using picosecond pulses at 355 nm for carrier excitation. In-plane diffusion and recombination of carriers, confined in the front layer of 50-nm-thick InGaN, were monitored by a delayed probe beam at 1064 nm. Decay times of free carrier gratings with various spatial periods allowed determination of bipolar diffusion coefficient D = 2.1 cm2/s, effective carrier lifetime of 470 ps, and estimate the corresponding hole mobility 40 cm2/Vs at carrier density of about 1018 cm−3. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)