Measurement of the Non-radiative Minority Recombination Lifetime and the Effective Radiative Recombination Coefficient in GaAs
The combination of time-resolved (TR) and power-dependent relative (PDR) photoluminescence (PL) measurements reveals the possibility of separating the radiative and non-radiative minority carrier lifetimes and measuring the sample-dependent effective radiative recombination coefficient in direct bandgap semiconductors. To demonstrate the method, measurements on 2 mm thick p-type GaAs double-hetero structures were conducted for various doping concentrations in the range of 5x1016 and 1x1018 cm-3. With a photon recycling factor of 0.76 ± 0.04 the radiative recombination coefficient was determined to be (3.3±0.6)×10-10 cm3s-1 for the structures with a doping concentration below 1*1018 cm-3, whereas the effective radiative recombination parameter for an absorber thickness of 2 mm was directly measured to be (0.78±0.07) ×10-10 cm3s-1. For a doping concentration of 1×1018 cm-3, the radiative recombination coefficient decreases significantly probably due to the degeneracy of the semiconductor.