Wide-Range-Tunable p-Type Conductivity of Transparent CuI1-xBrxAlloy

Transparent p-type semiconductors with wide-range tunability of the hole density are rare. Developing such materials is a challenge in the field of transparent electronics that utilize invisible electric circuits. In this paper, a CuI-CuBr alloy (CuI1-xBrx) is proposed as a hole-density-tunable p-type transparent semiconductor that can be fabricated at room temperature. First-principles calculations predict that the acceptor state originating from copper vacancies in CuBr is deeper than that in CuI, leading to the hypothesis that the hole density in CuI(1-)(x)Br(x)can be tuned over a wide range by varyingxbetween 0 and 1. The experimental results support this hypothesis. The hole density in CuI(1-)(x)Br(x)polycrystalline alloy layers can be tuned by over three orders of magnitude (10(17)-10(20)cm(-3)) by varyingx. In other words, the p-type conductivity of the CuI(1-)(x)Br(x)alloy shows metallic and semiconducting properties. Such alloy layers can be prepared at room temperature without sacrificing transparency. Furthermore, CuI(1-)(x)Br(x)forms transparent p-n diodes with n-type amorphous In-Ga-Zn-O layers, and these diodes have satisfactory rectification performance. Therefore, CuI(1-)(x)Br(x)alloy is an excellent p-type transparent semiconductor for which the p-type conductivity can be tailored in a wide range.