DYNAMICS OF PHOTOEXCITED CARRIERS IN ALXGA1-XN GAN DOUBLE HETEROSTRUCTURES/

We present results of a time-resolved photoluminescence study of the d ynamics of photoexcited carriers in AlxGa1-xN/GaN double heterostructu res (DHs). The carrier dynamics including generation, diffusion, spont aneous recombination, and nonradiative relaxation were studied by exam ining the time decay of photoluminescence associated with the spontane ous recombination from the samples. The temporal evolution of the lumi nescence from the GaN active layers of the DH samples was found to be governed by a carrier-diffusion dominated capture process. The determi nation of the capture rime for the carriers drift and diffusion into t he GaN active region, in addition to the effective lifetimes of the sp ontaneous recombination for carriers in the AlGaN cladding layers and the GaN active region, allows an estimation of the diffusion constants for the minority carriers in the AlxGa1-xN cladding layers of the DHs . Our results yield a diffusion constant of 2.6 cm(2)/s for Al0.03Ga0. 97N and 1.5 cm(2)/s for Al0.1Ga0.9N at 10 K. (C) 1997 American Institu te of Physics.