Two-dimensional electron gases in MgZnO/ZnO heterostructures.

The authors report investigations of two-dimensional electron gases (2DEG) formed due to the band offset and the change of the polarization at MgZnO/ZnO interfaces grown on sapphire substrates by pulsed-laser deposition. Capacitance-voltage measurements provide the means to resolve the electron density at the MgZnO/ZnO interface. The density of the 2DEGs is of the order 1011 cm-2 and much lower than expected from the change of polarization. The free electron density in the MgZnO is not sufficient to compensate the polarization charges. [ABSTRACT FROM AUTHOR]