Effect of V/III ratio on the properties of GaN layers grown by molecular beam epitaxy using NH3

Ammonia as nitrogen precursor has been used to grow m-V nitrides by molecular beam epitaxy (MBE) on c-plane sapphire substrates. The efficiency of NH3 has been evaluated allowing the determination of the actual V/III flux ratio used during the GaN growth. The effects of the V/III ratio variation on the GaN layer properties have been investigated by photoluminescence (PL), Hall measurements, atomic force microscopy (AFM), and secondary ion mass spectroscopy (SIMS). It is found that a high V/III ratio leads to the best material quality. Optimized GaN thick buffer layers have been used to grow GaN/AlGaN quantum well (QW) heterostructures. Their PL spectra exhibit well resolved emission peaks for QW thicknesses varying from 3 to 15 monolayers. From the variation of the QW energies as a function of well width, a piezoelectric field of 450 kV/cm is deduced.

Published in:
Wide-Bandgap Semiconductors For High Power, High Frequency And High Temperature, 512, 69-74
Presented at:
Symposium on Wide-Bandgap Semiconductors for High Power, High Frequency and High Temperature, SAN FRANCISCO, CA, Apr 13-15, 1998
Materials Research Society

 Record created 2010-10-13, last modified 2018-09-13

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