Influence of Ga/N ratio on morphology, vacancies, and electrical transport in GaN grown by molecular beam epitaxy at high temperature

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© 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and the American Institute of Physics. The following article appeared in Applied Physics Letters. Volume 97, Issue 19 and may be found at http://scitation.aip.org/content/aip/journal/apl/97/19/10.1063/1.3514236.

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2010

Major/Subject

Mcode

Degree programme

Language

en

Pages

191915/1-3

Series

Applied Physics Letters, Volume 97, Issue 19

Abstract

The effect of Ga/N flux ratio on surface morphology, incorporation of point defects and electrical transport properties of GaN films grown by plasma-assisted molecular beam epitaxy in a recently developed high-temperature growth regime was investigated. The homoepitaxial (0001) GaN films grown at ∼780–790 °C showed smoothest morphologies near the cross-over between N-rich and Ga-rich growth(0.75<Ga/N<1.1) contrasting previous observations for low-temperature growth. The higher-quality growth near Ga/N∼1 resulted from lower thermal decomposition rates and was corroborated by slightly lower Ga vacancy concentrations [VGa], lower unintentional oxygen incorporation, and improved electron mobilities. The consistently low [VGa], i.e., ∼10exp16 cm−3 for all films attribute further to the significant benefits of the high-temperature growth regime.

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Keywords

GaN, MBE, vacancies, positrons

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Citation

Koblmuller, G. & Reurings, F. & Tuomisto, Filip & Speck, J. S.. 2010. Influence of Ga/N ratio on morphology, vacancies, and electrical transport in GaN grown by molecular beam epitaxy at high temperature. Applied Physics Letters. Volume 97, Issue 19. 191915/1-3. ISSN 0003-6951 (printed). DOI: 10.1063/1.3514236