The influence of growth temperatures on the characteristics of GaN nanowires: The Raman study

The study of Raman scattering of GaN nanowires under different growth temperatures (750 °C to 1000 °C) is presented. GaN nanowires grown at 950 °C possessed the highest crystallinity. The Raman measurement illustrated E2(high) mode experienced a blueshift at lower temperature and redshift with the rising growth temperatures. This was related to the presence of stress/strain and the considerable oxygen content in the nanowires. By using Raman line shape analysis, the carrier concentration and mobility at different growth temperatures were determined which varied in the range of 4.0×1016 cm−3 to 5.27×1017 cm−3 and 158.2 cm2/V s to 376.2 cm2/V s, respectively. A comparative analysis of GaN thin film and nanowires revealed that the decreasing dimension of nanowires caused the broadening and lower frequency shift of Raman spectrum.