Effects of Homogeneous Buffer Layer on the Crystalline Quality and Electrical Properties of CdZnTe Epitaxial Films

The carrier transport process in CdZnTe epitaxial films is significantly influenced by the substantial lattice mismatch between the CdZnTe films and GaAs substrates. To mitigate this issue, a uniform buffer layer was fabricated between the substrates and the CdZnTe films using the close-space sublimation (CSS). The impact of the buffer layers on surface roughness and crystalline quality of the films was investigated through optical microscopy, atomic force microscopy, and X-ray diffraction. The effects on the electrical performance were studied through I-V tests and alpha-particle energy spectra. The results demonstrate that a uniform buffer layer, grown at 400°C for 5 min, significantly enhances the crystalline quality, resistivity, and carrier transport properties of the CdZnTe epitaxial films grown on low-resistance GaAs(001) substrates. After annealing at 400°C in a Te2 atmosphere for 4 h, the energy resolution of the detector improved to 1.5% in vacuum and 11.23% in air conditions.