Magneto-Optic Studies of GaN Films and GaN/AlGaN Heterostructures

ABSTRACTMagneto-studies have been carried out for several MOCVD grown GaN thin films and GaN/AlGaN heterostructures at magnetic fields up to 30 T and at temperatures between 4.2 K to 100 K. Electron cyclotron resonance was observed in two heterostructures with high mobilities (μ > 2000 cm2/V-s), the effective mass obtained from the cyclotron resonance measurement is 0.23±0.01 m0, where m0 is the mass of free electron. For Si-doped thin film GaN there was no sign of electron cyclotron resonance even when samples were heated up to 100 K. However, a Is to 2p+ absorption line was observed for Si-doped GaN samples. A binding energy of 29 meV and low frequency dielectric constant of 10.4 is obtained.