Influence of Polarization Effects on the Energy Band of AlGaN/GaN/AlGaN Heterostructures

摘要

The unintentionally doped samples of Al_(0.22)Ga_(0.78)N/GaN/Al_(0.22)Ga_(0.78)N/GaN multi-heterostructures have been designed and fabricated. The polarization induced charge and free-carrier charge distributions have been demonstrated and the energy band profile has also been calculated. The results indicate the existence of two-dimensional electron gas (2DEG) and hole well at the heterointerfaces. By means of variable temperature Hall measurements, the carrier mobility and the sheet carrier density were measured from 300 to 77 K. The significant increment of carrier mobility at low temperature also verified the existence of the 2DEG.