Modulation Spectroscopy of Cubic-GaN Semiconductor

• Main Authors: Chen-Wei Hsu, 許程為
• Other Authors: Ying-Sheng Huang
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/43866156369100035247

碩士 === 國立臺灣科技大學 === 電子工程系 === 89 === We have performed contactless electroreflectance (CER) and piezoreflectance (PzR) and photoreflectance (PR) measurements in studying the near band edge interband transitions of a cubic GaN film grown on GaAs (001) substrate by molecular beam epitaxy and metalorganic chemical vapor deposition. For the samples, both the excitonic transition and the transition from the spin-orbit splitting in the valence band ( ) are observed. The parameters that describe the temperature dependence of the energies have been analyzed by both the Varshni equation and an expression containing the Bose-Einstein occupation factor for phonons. For the samples grown by metalorganic chemical vapor deposition, the temperature dependence of the broadening parameter has also been studied in terms of Bose-Einstein equation that contains the electron (exciton)- longitudinal optical (LO) phonon coupling constant. The obtained parameters are compared with those of wurtzite GaN. The energy gap and the parameters which describe the temperature dependence of E0(T) for cubic GaN are found to be lower than that of hexagonal GaN