Polarization discontinuity induced two-dimensional electron gas at ZnO/Zn(Mg)O interfaces: A first-principles study

Authors

Jesuan Betancourt, University of Puerto Rico - San Juan
J. J. Saavedra-Arias, University of Puerto Rico - San Juan
John D. Burton, University of Nebraska-LincolnFollow
Yasuyuki Ishikawa, University of Puerto Rico - San JuanFollow
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
Julian P. Velev, University of Puerto Rico-San JuanFollow

Date of this Version

8-14-2013

Citation

PHYSICAL REVIEW B 88, 085418 (2013). 10.1103/PhysRevB.88.085418

Comments

Copyright (c) 2013 American Physical Society. Used by permission.

Abstract

The discovery of a high-mobility two-dimensional electron gas (2DEG) in wurtzite ZnO/Zn(Mg)O heterostructures is promising for applications due to the high mobility of the carriers. In this paper, we study the formation and properties of the 2DEG at ZnO/Zn(Mg)O interfaces using first-principles calculations based on hybrid density functional theory. The 2DEG arises from the polarization discontinuity at the interface between the two materials. The uncompensated bound charge at the interface gives rise to an electric field in the bulk of ZnO which confines free carriers close to the interface. We find that the type of the confined carriers is determined by the interface termination, while the amount of charge and the confinement width could be controlled by the Mg doping and the device dimensions.