Evaluating Sulfur as a P‐Type Dopant in Cu3N Using Ab Initio Methods

Abstract

Copper nitride (Cu3N) is an environmentally friendly semiconducting material with bipolar doping capability and is of interest to various applications. As deposited Cu3N films have inherent n‐type conductivity, further controllable n‐type doping is possible by introducing metal impurities. First‐principles methods based on density functional theory and beyond have been employed to study the p‐type doping behavior of sulfur atoms in Cu3N. The structural, electronic, optical, and thermal properties of pure Cu3N and sulfur‐doped Cu3N are computed for single and 3 × 3 × 3 supercells. Sulfur doping causes a shift from intrinsic n‐type to p‐type behavior. This study confirms that sulfur atoms in sulfur‐doped copper nitride preferentially occupy interstitial positions over nitrogen substitution, face‐centered, or copper substitution sites. Due to this change and an increased lattice constant, Cu3N becomes a softer material with a larger bandgap in the single‐cell alloy. Doped Cu3N supercell results show significant changes in optical properties appropriate for solar and other photoelectric applications. Cu3N:S exhibits remarkable enhancements in power factor and thermal and electrical conductivity, indicating potentially better performance in thermoelectric applications. The dielectric constant and absorption coefficient also significantly change with the incorporation of sulfur into Cu3N.