Time-resolved and excitation-dependent photoluminescence study of CdTe/MgCdTe double heterostructures grown by molecular beam epitaxy

Abstract

This Letter reports the optical properties of CdTe/MgCdTe double heterostructures grown by molecular beam epitaxy. Low-temperature photoluminescence shows strong band-to-band emission and very weak defect related peaks, indicating low defect densities. The measured Shockley–Read–Hall lifetimes range from 57 to 86 ns at room temperature for samples grown under different conditions. The material radiative recombination coefficient B in the recombination rate defined as R=AΔn+(1−γ)BΔn2+CΔn3 [Wang et al., Phys. Status Solidi B 244, 2740 (2007)] is evaluated to be 4.3 ± 0.5 × 10−9 cm3·s−1 with a photon recycling factor γ of 0.85 calculated based on the geometric structure of the samples.