(111)-Oriented Growth and Acceptor Doping of Transparent Conductive CuI:S Thin Films by Spin Coating and Radio Frequency-Sputtering

Anion doping is an efficient method for modifying the electrical property of the p-type semiconductor CuI. However, adjustment of the hole density is still challenging. Using sputtering and spin coating techniques, well-controlled S-doping of CuI thin films has been realized. The spin-coated samples present a single (111) out-of-plane orientation and very high crystallinity, which is comparable with previously reported epitaxial CuI thin films. The sputtered thin films have advantages in surface morphology and conductivity. Substituting S for I can achieve efficient acceptor doping of CuI for both the physical and chemical growth methods. The highest conductivity of CuI appears at 2.0 at% of S doping, and the doping efficiency is influenced by the self-compensation effect.