A New Highly Conductive Direct Gap p-Type Semiconductor La<sub>1–<i>x</i></sub>Y<i><sub>x</sub></i>CuOS for Dual Applications: Transparent Electronics and Thermoelectricity
Nengduo Zhang, Xixia Liu, David Boon Kiang Lim, Hao Gong
Abstract
The absence of a high-performance p-type transparent semiconductor still remains as a roadblock to the development of future generation optoelectronics. Here, a highly conducting p-type transparent semiconductor based on Y incorporated LaCuOS oxychalcogenide is achieved for the first time, and the maximum Y substitution to obtain a single phase is found to be 25%. By enhancing both the hole mobility and concentration of the LaCuOS phase, Y-substituted oxychalcogenide single-phase La0.75Y0.25CuOS exhibits an outstanding p-type conductivity of 89.3 S·cm–1 with high optical transparency, which is the highest among all transparent oxychalcogenides with a band gap above 3 eV reported so far. The structural, electronic, and optical as well as the thermoelectric properties of La1–xYxCuOS with a different Y substitution level are investigated, and the power factor was greatly enhanced to 4.322 μW m–1 K–2 after Y substitution. The highly performing diode based on a p-type La0.75Y0.25CuOS thin film and n-type Al-doped ZnO heterojunction with a high rectifying ratio of 300 is demonstrated, indicating its promising aspect for the next generation of invisible electronics and optoelectronics.