Hole transport and carrier lifetime in InN epilayers

Time-resolved transient grating spectroscopy has been conducted to measure the ambipolar diffusion coefficient and to derive the hole mobility and carrier lifetime in an InN epilayer simultaneously. The ambipolar diffusion coefficient D-a=2.0 cm(2)/s, hole mobility mu(h)=39 cm(2)/V s, and carrier lifetime tau(R)=5.4 ns at 300 K near the InN surface were determined by monitoring the transient grating kinetics at various grating periods. In addition, we observed a decrease of hole mobility and carrier lifetime at the internal epilayer/buffer interface in comparison with those at the free surface, suggesting a faster carrier capture rate to the defect states and a more efficient defect and impurity scattering mechanism. (c) 2005 American Institute of Physics.