Raman scattering and photoluminescence of zinc telluride nanopowders at room temperature

Zinc telluride (ZnTe) powders were synthesized in sodium hydroxide solution by the hydrothermal method under different conditions, in which zinc and tellurium powders were used as precursors. Their structures were characterized by X-ray diffractometer, X-ray photoelectron spectroscopy, transmission electron microscopy, and micro-Raman spectrometer. The results indicate that the powders are composed of ZnTe nanocrystals with zincblende structure and contain some impurities, and the average sizes of ZnTe nanocrystals are about 67, 92, and 112 nm when they were grown at 120 °C for 1, 2, and 6 h, respectively. The Raman spectra show three peaks centered at about 205, 410, and 616 cm⁻¹, which are attributed to the longitudinal optical phonon vibration modes of ZnTe. The photoluminescence (PL) of ZnTe nanopowders were also investigated at room temperature and the PL spectra show three emission peaks at about 555, 578, and 701 nm, which are related to the complex defects and isolelectronic oxygen trap.