Study on precipitates in AgGaSe2 single crystal grown by vertical gradient freezing method

Abstract

Abstract In this study, AgGaSe2 single crystal was successful grown by vertical gradient freezing method. Meanwhile, the precipitates on AgGaSe2 single crystal were investigated by x-ray photoelectron spectroscopy (XPS). This technique was recommended as a practicable method to study the precipitates while they are difficult to be detected by other measurements owing to their components and fairly low content. In addition, Energy Disperse Spectroscopy (EDS) and x-ray diffraction (XRD) were employed to characterize the quality of the as-grown AgGaSe2 single crystal. The EDS results indicate a slight deviation from stoichiometric ratio along growth defects. The XRD results manifest that AgGaSe2 crystal has single phase and high purity. The XPS results indicate that precipitates exist on as-grown AgGaSe2 single crystal mainly in the form of Ga2Se3. Ga2O3 and Ag2O were detected by XPS on the polished surface of the as-grown crystal wafer which was regarded as an oxide layer. The study on precipitates may provide important reference for growth process improvement and post-treatment to obtain high quality AgGaSe2 single crystal.