Landau level quantization with gate tuning in an AlN/GaN single heterostructure

The transport properties in an AlN/GaN single heterostructure grown on a GaN substrate were investigated over a temperature range between 0.25 and 300 K under magnetic fields of up to 15 T. The electron density was successfully controlled over the entire temperature range by applying gate voltage through an Al2O3 gate insulator. At low temperatures, clear Landau level quantization, which depends on the electron density, was observed.