First-principles calculations of phosphorus-doped SnO2 transparent conducting oxide: Structural, electronic, and electrical properties

The structural and electronic properties of phosphorus-doped tin oxide (PTO) were investigated by density functional theory (DFT). The lattice parameters computed with the Perdew-Burke-Ernzerhof (PBE) functional were decreased as phosphorus (P) impurities were substituted for Sn cations. The band structure of PTO computed with the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional showed an optical energy bandgap widening effect, because of a large Moss-Burstein shift and a small exchange–correlation-induced bandgap narrowing. Also, the P impurities in SnO2 induced shallow donor P-3s states in the conduction band minimum near Fermi level. The electron effective mass of the systems was calculated to be 0.25 m0. DFT calculations also predicted a 5.9 × 1020 cm−3 electron density for PTO, which could increase the electrical conductivity of SnO2. These features make PTO a promising material for transparent conducting applications.