Properties of the Two-Dimensional Electron-Gas of a Hybrid MgZnO/InGaN/ZnO Heterostructure with an InGaN Channel Layer

The polarization effect on a two-dimensional electron gas (2DEG) in a the ZnO/InGaN/MgZnO high electron mobility transistor (HEMT) was theoretically investigated as a function of the In content and the InGaN layer thickness. The electron density in the ZnO/InGaN/MgZnO HEMT is shown to be enhanced with increasing In content. In particular, in the case of the HEMT structure with a relatively high In content of 0.2, we find that the confinement of the electron gas is signifi- cantly improved. Also, the electron density increases linearly with increasing layer thickness because the potential difference between the MgZnO/InGaN and the InGaN/ZnO interfaces increases with increasing layer thickness. As a result, the carrier confinement in the MgZnO/InGaN/ZnO HEMT structure is shown to be superior to that in the conventional MgZnO/ZnO HEMT structure.