Effects of annealing on the properties of CdZnTe epitaxial thick films deposited on p-GaAs using close-spaced sublimation

CdZnTe epitaxial thick films were deposited on p-type GaAs (001) substrates using close-spaced sublimation. In order to reduce defects in the CdZnTe/p-GaAs films and improve the carrier transport properties, isothermal annealing in a Te₂ atmosphere was carried out. After annealing, the resistivity of the CdZnTe/p-GaAs samples increased and the leakage current decreased. In addition, the electron mobility and lifetime product μτ_e, measured by fitting ²⁴¹Am@5.49 MeV α particles energy spectra with the Hecht equation using full peak channels under different voltages, were improved. Finally, a ²⁴¹Am@59.5 keV γ ray energy spectrum of an annealed CdZnTe/p-GaAs sample was acquired. According to the etch pit density and photoluminescence spectrum, it was suggested that isothermal annealing reduced the dislocation density in the as-deposited CdZnTe films and therefore improved the performance of the annealed detectors.