Numerical optimization of two-dimensional electron gas in Mg_xZn_1−xO/ZnO heterostructures (0.10 < x < 0.30)

Abstract

One-dimensional, self-consistent Schrödinger–Poisson equations are solved for the wurtzite Mg _x Zn_{1− x} O/ZnO heterostructure (0.1 < x < 0.3). For the [] orientation, a polarization-induced two-dimensional electron gas (2DEG) is found to be populated at the pseudo-triangular quantum well (QW) that is formed at Mg _x Zn_{1− x} O/ZnO interface. The effects of different Mg mole fractions and different Mg _x Zn_{1− x} O barrier thicknesses on the band structure, charge densities and electron probability densities are calculated. Formation of a second subband is found to never exist under strained conditions for the investigated structures. By including the effect of QW width on mobility of the 2DEG, a structure with x = 0.15 and a barrier thickness of 22 nm has been suggested for high temperature applications.

Keywords:

• Schrödinger–Poisson equations
• simulation
• ZnO
• oxide electronics
• MgZnO
• optimization
• barrier thickness
• quantum well
• two-dimensional electron gas

Acknowledgements

This work is supported by the project Gazi BAP-05/2012-13.