Density functional theory study on defect feature of AsGaGaAs in gallium arsenide

Abstract

We investigate the defect feature of A s Ga G a As defect in gallium arsenide clusters in detail by using first-principles calculations based on the density functional theory (DFT). Our calculations reveal that the lowest donor level of A s Ga G a As defect on the gallium arsenide crystal surface is 0.85 eV below the conduction band minimum, while the lowest donor level of the A s Ga G a As defect inside the gallium arsenide bulk is 0.83 eV below the bottom of the conduction band, consistent with gallium arsenide EL2 defect level of experimental value (Ec-0.82 eV). This suggests that A s Ga G a As defect is one of the possible gallium arsenide EL2 deep-level defects. Moreover, our results also indicate that the formation energies of internal A s Ga G a As and surface A s Ga G a As defects are predicted to be around 2.36 eV and 5.54 eV, respectively. This implies that formation of A s Ga G a As defect within the crystal is easier than that of surface. Our results offer assistance in discussing the structure of gallium arsenide deep-level defect and its effect on the material.