Radiative and nonradiative recombination rates in cubic SiC

Abstract

Investigation of carrier dynamics in highly excited 3C–SiC by free-carrier absorption and photoluminescence (PL) techniques allowed determination of nonradiative and radiative recombination rates. Free carrier decay kinetics at various injection levels provided nonradiative recombination coefficients: bimolecular Bnr and Auger, C. By modelling carrier in-depth diffusion and taking into account nonlinear recombination rates, we fitted the experimental PL injection dependence and determined radiative bimolecular coefficient at room temperature, Brad=2.05×10−15cm3/s. A theoretically calculated value was found rather similar (2.38×10−15cm3/s). Numerical analysis of the injection-dependent PL spectra exhibited effects of bandgap filling and bandgap renormalisation (BGR), providing the BGR coefficient aBGR=1.2×10−6eVcm3/4 and low injection bandgap value Eg0=2.374eV of a cubic SiC at room temperature.