Mg and N co-doped CuCrO2: A record breaking p-type TCO

Abstract

We prepare CuCrO2 thin films with magnesium and nitrogen dopants. The solid state reaction method is employed to produce CuCrO2 targets with three different concentrations of Mg (0%, 2.5%, and 5%). The targets are used in an RF sputtering system to prepare thin films in the presence of N2 as the reactive gas. In this manner, Mg and N atoms, respectively, replace Cr and O sites in the CuCrO2 structure and enhance the electrical and optical properties of the host material. This cationic-anionic substitution yields a superior hole transport and results in an increased conductivity of ∼278 S cm−1 which is considered as a record for p-type conductivity in transparent conducting oxides. Moreover, the co-doped CuCrO2 demonstrates a bandgap of 3.52 eV and a transmittance of about 69% in the visible region.

Functional Oxides for Photoneuromorphic Engineering: Toward a Solar Brain

“…Mg-doped CuCr 1-x Mg x O 2 ) has resulted in p-type layers with conductivities of up to ~200  -1 cm -1 . Analogously, the Mg and N substitution of Cr and O sites (in CuCrO 2 ) resulted in an increased conductivity of up to ∼278  -1 cm −1 [204] , which arguably is the largest conductivity for p-type Cu-based delaffosite oxides reported to date.…”

The Optoelectronic Properties of p-Type Cr-Deficient Cu[Cr0.95−xMg0.05]O2 Films Deposited by Reactive Magnetron Sputtering

“…where (Cr Cr ) × represents the Cr in the original lattice sites, (Mg Cr )' represents the Mg 2+ in Cr 3+ site and h + is the positive hole. To date, the highest p-type conductivity of about 278 S•cm −1 has been obtained in Mg and N co-doped CuCrO 2 film deposited by radiofrequency (RF) sputtering, where the Cu vacancies (V Cu ) as well as the substitution of Cr by Mg (Mg Cr ) and O by N (N O ) are considered as the intrinsic acceptor and extrinsic acceptor, respectively [23]. All of them contribute to the carrier concentration.…”

Transparent p-Type Semiconductors: Copper-Based Oxides and Oxychalcogenides

“…It was found that the p-type conductivity increased by more than three orders to 17 S•cm −1 compared to the intrinsic state [123]. By combining both cation and anion substitution, a new record for p-type conductivity in delafossites has been reported to be 278 S•cm −1 in 2018 [124]. In this study, Mg and N dopants were introduced into the CuCrO2 thin film, which served to substitute Cr and O, respectively.…”

“…Possibly because this paper was published just recently, no other reports on such a high conductivity for this system can be found. Besides the Mg-N doping, other co-doping strategies have also been studied, including Mg-Fe [133], Mg-S [137], and Ag-Mg [138], but the electrical and optical properties are not comparable to the study on Mg-N doping [124].…”