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.