The growth and the interfacial layer of CdZnTe nano-crystalline films by vacuum evaporation

Nano-crystalline CdZnTe films were fabricated by thermal vacuum evaporation. The structure and surface morphology of the CdZnTe films were determined by XRD and SEM. The CdZnTe films were poly-crystalline with preferential (111) orientation. The CdZnTe films exhibited a typical particle size of 15 nm and a blue shift in the absorption with an effective band gap of 2.26 eV. An amorphous Te interfacial layer with thickness of 3 nm was observed with high resolution transmission electron microscopy, which should be formed at the initial stage of the growth. This is because the equilibrium vapor pressure of Cd is largely higher than that of Te₂ at the growth temperature, and the desorption rate of Cd atoms is much higher than that of and Te ₂ molecules. The amorphous interfacial layer should be favorable for the formation of nano-crystalline CdZnTe film.