Dissociation of VGa-ON complexes in HVPE GaN by high pressure and high temperature annealing

• Published in: Physica Status Solidi (b) 2006-06, Vol.243 (7), p.1436-1440
• Main Authors: Tuomisto, F., Hautakangas, S., Makkonen, I., Ranki, V., Puska, M. J., Saarinen, K., Bockowski, M., Suski, T., Paskova, T., Monemar, B., Xu, X., Look, D. C.
• Format: Article
• Language: English
• Subjects: 61.72.Cc; 61.72.Ji; 71.55.Eq; 78.70.Bj; 81.15.Kk; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other interactions of matter with particles and radiation; Physics; Point defects (vacancies, interstitials, color centers, etc.) and defect clusters; Positron annihilation; Structure of solids and liquids; crystallography
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200565109

We have used positron annihilation spectroscopy to study the high‐pressure annealing induced thermal recovery of vacancy defects in free‐standing GaN grown by hydride vapor phase epitaxy (HVPE). The results show that the in‐grown Ga vacancy complexes recover after annealing at 1500–1700 K. Comparison of the experimental positron data with ab‐initio calculations indicates that the Doppler broadening measurement of the electron momentum distribution is sensitive enough to distinguish between the N and O atoms surrounding the Ga vacancy. We show that the difference between the isolated VGa in electron irradiated GaN and the VGa–ON complexes in highly O‐doped GaN is clear, and the Ga vacancy related defect complexes that start dissociating at 1500 K can be identified as VGa–ON pairs. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)