Based on density functional theory, the electronic structure and optical properties were calculated for two-dimensional GaN and its Ga, N vacancy systems. The stability of GaN with vacancy defects was analyzed by calculating the formation energy. The band structure and state density were then calculated. The effect of vacancy defects on absorption spectra was analyzed and discussed. The results show that the formation energy of Ga-N vacancies is the smallest and is the easiest to form. The Ga vacancies make the two-dimensional GaN exhibit p-type semiconductor characteristics, while the N vacancies make it exhibit n-type semiconductor characteristics. The vacancy defects improve the electron mobility and optical response of the two-dimensional GaN. The absorption spectra of all two-dimensional GaN with vacancy defects are redshifted from perfect ones with higher absorption coefficients in the low-energy region, which indicates that the generation of Ga and N vacancies can improve the visible light absorption.
维普
万方数据