Keywords: Ga2O3 nanowires, nanoribbons, VLS growth, electron spin resonance, photoluminescence, gas sensors, nanosensors, nanotechnology
Study of defect behaviour in Ga2O3 nanowires and nano-ribbons under reducing gas annealing conditions: applications to sensing
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.