Stability and band gaps of InGaP, BGaP, and BInGaP alloys: Density-functional supercell calculations

Abstract

Energies and band gaps of (InGa)P, (BGa)P and (BInGa)P alloys, including the antisite boron substitutions, are calculated using supercells and the density-functional method. The influence of the substituent concentration and arrangement on the stability and band gaps is investigated and compared with experimental findings. Linearly corrected band-gap widths reproduce well experimental and GW data. The most stable structures of the ternary alloys are 200/211 arrangements of the substituents. The T–x phase diagram for (InGa)P provides no miscibility gap for usual growth temperatures. However, for (BGa)P alloys a large miscibility gap is obtained between about 2% and 99% boron, what confirms experimental results. In quaternary (BInGa)P, boron and indium atoms prefer the (220) but also the (110) position to each other. A 2:1 ratio is preferred for the indium to the boron content. Supercell with the most probable B1InnGa31−nP32 structure (n = 2).