Composition dependent band offsets of ZnO and its ternary alloys

Haitao Yin; Junli Chen; Yin Wang; Jian Wang; Hong Guo

doi:10.1038/srep41567

Composition dependent band offsets of ZnO and its ternary alloys

Sci Rep. 2017 Jan 30:7:41567. doi: 10.1038/srep41567.

Authors

Haitao Yin^{1

2}, Junli Chen¹, Yin Wang^{2

3}, Jian Wang^{2

3}, Hong Guo^{2

4}

Affiliations

¹ Key Laboratory for Photonic and Electronic Bandgap Materials of Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, China.
² Department of Physics and the Center of Theoretical and Computational Physics, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China.
³ The University of Hong Kong Shenzhen Institute of Research and Innovation, Shenzhen, Guangdong 518057, China.
⁴ Center for the Physics of Materials and Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada.

Abstract

We report the calculated fundamental band gaps of wurtzite ternary alloys Zn_1-xM_xO (M = Mg, Cd) and the band offsets of the ZnO/Zn_1-xM_xO heterojunctions, these II-VI materials are important for electronics and optoelectronics. Our calculation is based on density functional theory within the linear muffin-tin orbital (LMTO) approach where the modified Becke-Johnson (MBJ) semi-local exchange is used to accurately produce the band gaps, and the coherent potential approximation (CPA) is applied to deal with configurational average for the ternary alloys. The combined LMTO-MBJ-CPA approach allows one to simultaneously determine both the conduction band and valence band offsets of the heterojunctions. The calculated band gap data of the ZnO alloys scale as E_g = 3.35 + 2.33x and E_g = 3.36 - 2.33x + 1.77x² for Zn_1-xMg_xO and Zn_1-xCd_xO, respectively, where x being the impurity concentration. These scaling as well as the composition dependent band offsets are quantitatively compared to the available experimental data. The capability of predicting the band parameters and band alignments of ZnO and its ternary alloys with the LMTO-CPA-MBJ approach indicate the promising application of this method in the design of emerging electronics and optoelectronics.

Publication types

Research Support, Non-U.S. Gov't