Title: Study of defect behaviour in Ga₂O₃ nanowires and nano-ribbons under reducing gas annealing conditions: applications to sensing

Authors: S.M. Prokes, W.E. Carlos, E.R. Glaser

Addresses: US Naval Research Laboratory, 4555 Overlook Ave. SW, Washington DC 20375, USA. ' US Naval Research Laboratory, 4555 Overlook Ave. SW, Washington DC 20375, USA. ' US Naval Research Laboratory, 4555 Overlook Ave. SW, Washington DC 20375, USA

Abstract: The growth of monoclinic Ga₂O₃ nanowires, nano-ribbons and nano-sheets has been investigated. Results indicate that high quality single crystal nanowires can be grown at 900°C using an Au catalyst, while single crystal nano-ribbons and nano-sheets require no metal catalyst for growth. Since bulk Ga₂O₃ is a promising material for high temperature gas sensing, Ga₂O₃ nanowires and nano-ribbons may prove to enhance the sensing capability due to the high surface area. We have investigated the nature of defects in this material using electron spin resonance, photoluminescence and scanning electron microscopy, in as grown material, as well as under annealing in a reducing gas (H₂) at various high temperatures. Results indicate the presence of an oxygen deficiency in the material, resulting in a conduction electron signal that becomes enhanced with annealing. The eventual loss of this signal is attributed to hydrogen etching of the nanowires, leading to a loss of material.

Keywords: Ga₂O₃ nanowires; nanoribbons; VLS growth; electron spin resonance; photoluminescence; gas sensors; nanosensors; nanotechnology.

DOI: 10.1504/IJNT.2008.017448

International Journal of Nanotechnology, 2008 Vol.5 No.4/5, pp.475 - 487

Published online: 07 Mar 2008 *

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