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

J. Betancourt, J. J. Saavedra-Arias, J. D. Burton, Y. Ishikawa, E. Y. Tsymbal, and J. P. Velev

Phys. Rev. B 88, 085418 – Published 14 August 2013

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.

Received 25 March 2013

DOI:https://doi.org/10.1103/PhysRevB.88.085418

Authors & Affiliations

J. Betancourt¹, J. J. Saavedra-Arias², J. D. Burton³, Y. Ishikawa², E. Y. Tsymbal³, and J. P. Velev^1,3

¹Department of Physics, Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931, USA
²Department of Chemistry, Institute of Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931, USA
³Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, Nebraska 68588, USA

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Vol. 88, Iss. 8 — 15 August 2013

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