First-principles calculations on the diffusion and electronic properties of CuI doped by cation and anion

Abstract

CuI has attracted much attention for the optoelectronic devices due to the wide band gap of 3.1 eV (p-type). Previous theoretical and experimental results demonstrate doping successfully tunes stability of the intrinsic defects in CuI. We study the diffusion and electronic properties of CuI doped with Li, Na, Mg, F, Cl, and Br using first-principles calculations. Importantly, the low diffusion energy barriers (<0.6 eV) enable uniform distribution of the dopants. Br, Cl, and F at the I site reduce the band gap to 1.08, 1.06, and 1.00 eV as compared to 1.09 eV for undoped CuI. The anion at the interstitial site introduces some unoccupied states at 0.06 eV above the valence band maximum, enhancing the p-type conductivities.

Keywords

• CuI
• Doping
• Diffusion
• Electronic properties