High Electron Mobility Exceeding 104 cm2 in Mg ZnO Single Heterostructures Grown by Molecular Beam Epitaxy

Nominally undoped MgxZn1
xO/ZnO (x ¼ 0:05 and 0.08) single heterostructures were prepared on Zn-polar ZnO substrates by usingplasma assisted molecular beam epitaxy (MBE). The samples showed a metallic conductivity below 50K and a mobility exceeding104 cm2 V
1 s
1 at 0.5 K. We observed quantum Hall effect accompanying Shubnikov–de Haas oscillat..