Published online by Cambridge University Press: 31 January 2011
Photoluminescence (PL) and photo-induced-current transient spectroscopy measurements on As-doped CdTe/Cd0.96Zn0.04Te heterostructures grown by molecular beam epitaxy were carried out to investigate the optical properties and the annealing effects on the deep levels. The temperature dependence of the PL spectra showed that the luminescence intensity of the exciton peak related to the neutral acceptors (A°, X) decreased with increasing measurement temperature and that the activation energy of the (A°, X) peak for the As-doped CdTe epilayer was 7 meV. Five hole-trap peaks appeared for the annealed As-doped CdTe/Cd0.96Zn0.04Te heterostructure. Two of these peaks, denoted by H1 and H2, might be related to extrinsic impurities, and the other three peaks, represented by H3, H4, and H5, might be attributed to intrinsic impurities. These results can help improve understanding for the application of As-doped CdTe/Cd0.96Zn0.04Te heterostructures in optoelectronic devices.