Oxygen and temperature effects on NiO buffer layers for CdTe solar cells

Nickel oxide has been previously shown to improve CdTe when used as a buffer layer. NiO was sputtered under varying oxygen and heating conditions. NiO films were characterised to identify changing characteristics. Increasing oxygen increases optical transmission and decreases reflectance. Post annealing at ${300^{\circ}\mathrm{C}}$ has negligible effect on optical properties of NiO films. NiO with 5% oxygen/argon during deposition, without heating, produces the least sheet resistance of ${4.51\mathrm{x}10^{5}}$ Ω/square. These were then combined with CdCI treated CdTe and JV characteristics and carrier lifetimes measured and compared with a reference cell.