The effect of Bi-In hetero-antisite defects in In1-xPBix alloy

Artikel i vetenskaplig tidskrift, 2016

Bi-In hetero-antisite defects in InP:Bi alloy is performed by using first-principle calculations. It is found that the hetero-antisite defect Bi-In is energetically easier than BiP. This Bi-In defect is a deep level donor, and the related defect band is introduced by the sp-hybridization mainly between the 6s state of Bi-In and 3p states of the nearest P atoms. The band gap of InP:Bi alloy increases slightly with the increase of Bi compositions, and the relative position of the defect level remains almost unchanged. These results represent that hetero-antisite defect Bi-In does not contribute to the reduction of the band gap of InP:Bi alloy. The calculations of optical properties show that hetero-antisite defect Bi-In can contribute to the red shift phenomena observed in experiment as the Bi composition increases. In addition, the interaction of two Bi-In atoms can result in the split of the impurity band and cause a strong absorption in near-infrared region, indicating it can be a potential candidate for optoelectronics application.