MAGNETOOPTICAL STUDIES OF GAN AND GAN ALXGA1-XN - DONOR ZEEMAN SPECTROSCOPY AND 2-DIMENSIONAL ELECTRON-GAS CYCLOTRON-RESONANCE/

Magneto-optical experiments have been performed on free and bound elec trons in GaN films and GaN/AlGaN heterojunctions. Cyclotron resonance of two dimensional electron gas in GaN/AlxGa1-xN heterojunctions has y ielded m = 0.23 m(0), x-dependent scattering times consistent with va lues from transport measurements, and an apparent unexplained level cr ossing at 70 cm(-1). Infrared absorption of doped GaN films has shown that the binding energy of Si donors, 29.0 meV, is much smaller than t hat of residual donors, in agreement with transport measurements, thus suggesting donor spectroscopy as a useful technique for defect/impuri ty qualitative analysis. Zeeman effect of the donor spectra has been u sed to determine the GaN low frequency dielectric constant, epsilon(0) = 10.4. (C) 1996 American Institute of Physics.