Electronic and optical properties of ultrawide bandgap perovskite semiconductors via first principles calculations

摘要

Recent research in ultrawide-bandgap (UWBG) semiconductors has focused on traditional materials such as Ga_2O3_, AlGaN, A1N, cubic BN, and diamond; however, some materials exhibiting a single perovskite structure have been known to yield bandgaps above 3.4 eV, such as BaZrO_3 In this work, we propose two materials to be added to the family of UWBG semiconductors: Ba_2CaTeO_6 exhibiting a double perovskite structure and Ba_2K_2Te_2O_9 with a triple perovskite structure. Using first-principles hybrid functional calculations, we predict the bandgaps of all the studied systems to be above 4.5 eV, with strong optical absorption in the ultraviolet region. Furthermore, we show that holes have a tendency to get trapped through lattice distortions in the vicinity of oxygen atoms, with an average trapping energy of 0.25 eV, potentially preventing the enhancement of p-type conductivity through traditional chemical doping.