Photoluminescence of Crystalline cDtE double heterostructures grown by MBE

Abstract

Low-temperature photoluminescence (LTPL) and time-resolved photoluminescence (TRPL) were used to study bulk material and interface properties of MBE-grown CdTe. CdTe and CdTe ternary-alloy double heterostructures (DH) grown on CdTe and InSb substrates show LTPL emission from excitons, dislocations, and other defects. Photoluminescence spectra changed with material composition and quality, with near-band exciton emissions increasing and emissions related to extended and point defects decreasing as defect density decreased and interfaces improved. Measured lifetimes from TRPL decay curves also reflected the quality of the DHs. Data showed that overall DH quality depends more upon buffer thicknesses than absorber layer thicknesses. CdTe/CdMgTe DHs grown on InSb substrates had the highest near-band PL and lowest defect emission as seen in low-temperature spectral emission and highest lifetimes in TRPL data.