Electron-spin-resonance studies of donors in wurtzite GaN

Physical Review B 48(24), 17878 (1993).

Electron-spin-resonance (ESR) measurements have been performed on a series of wurtzite GaN films grown on sapphire substrates by low-pressure metal-organic chemical-vapor deposition. The sample set included films grown with both AlN and GaN buffer layers. The ESR signal results from residual donors with g_{|| (parallel)} =1.9510 and g_{(perpendicular)} =1.9483. The g value and the effective mass can be explained using a five-band k (center-dot) p model. Nuclear hyperfine interactions are observed as a shift in the central resonance position, due to the Overhauser effect from which the density of the wave function at the Ga nucleus is derived. The ESR lines all have quite a sharp Lorentzian shape due to motional narrowing. At low temperatures (T<20 K) the linewidth narrows with increasing temperature, consistent with electrons hopping from donor site to donor site. At higher temperatures the line broadens due to electron-phonon interactions. The concentration of uncompensated donors is independent of film thickness for GaN buffered films but increases monotonically with thickness for AlN buffered films, probably due to a decrease in the concentration of compensating centers. Photoluminescence measurements indicate that only the thickest films are homogeneous along the growth direction.

This item is cited by the following items in the database:

1. Optical Detection of Electron Nuclear Double Resonance on the Residual Donor in GaN
2. AVALANCHE BREAKDOWN LUMINESCENCE OF InGaN/AlGaN/GaN HETEROSTRUCTURES
3. AMMONO method of BN, AlN and GaN synthesis and crystal growth.
4. Luminescence and ESR Spectra of GaN:Si below and above Mott Transition
5. Paramagnetic defects in GaN

Contributed by F. K. Koschnick from cip5.uni-paderborn.de. on Thursday, May 30, 1996 5:22:15 AM
Modified by Andrei Nikolaev from shuttle.ioffe.rssi.ru

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