Nonequilibrium Carrier Dynamics in DPB-Free 3C-SiC Layer Studied by Dynamic Grating Technique in Wide Excitation and Temperature Range

Abstract

We applied picosecond dynamic grating technique for studies of carrier dynamics in ntype DPB(double positioning boundary)-free 3C-SiC (111) epilayer grown by VLS (vapour-liquidsolid) mechanism on 6H-SiC (0001). The measurements of bipolar diffusion coefficient D and carrier lifetime τR in the samples at various pump energies (0.5 – 3.0 mJ/cm2) and temperatures (9 – 300 K) provided the values of bipolar mobility of ~ 80 cm2/Vs and τR = 1.5 - 2.0 ns at 300 K. The ionized impurity scattering, dominant at T < 100 K, and carrier-density dependent lifetimes in 10- 300 K range were attributed to contribution of trapping centers which electrical activity saturates at high carrier density.