Photoluminescence Study of GaN by Controlling the Carrier Gas H2/N2 Ratio

• Main Author: 曾仕君
• Other Authors: Amy H.-M. Chu
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/65430473485409250928

碩士 === 中原大學 === 物理學系 === 88 === This study is concerned entirely with a series of GaN films grew using different carrier gas hydrogen to nitrogen ratio by lower pressure metalorganic chemical vapor deposition (LP-MOCVD), simultaneously, we investigate the variation of the band edge and deep level spectrum under different growth conditon of hydrogen to nitrogen ratio by photoluminescence mechanism. The PL spectra revealed the band edge emission peaks at 3.4~3.5 eV and a broad deep level band at 2.2 eV. We also found that the band edge emitting line moved gradually to lower energy position with increasing the temperature, which is so called the red shift. Recently we are showing that the intensity ratio of band edge (BE) bands to yellow (YL) peaks will decrease with increasing measurement temperature under the H2/N2 ratio are 1500/500 and 1000/1000, respectively. It is due to the vacancies and stress slack existing in the specimen during cooling down process. And the deep level peak is caused by the Ga vacancy recombination. Apart from the results of BE band and YL peak, the magnitudes of full width at half maximum (FWHM) will increase with increasing the measurement temperature. The phenomenal of result is caused by the exciton-phonon interaction at high temperature. From the previous mentioned results, one can effectively control the band edge luminescence with few meV under the optimum growth condition.