Abstract
In2O3 micro-rods consisting of In2O3 rods with pyramid-like shape structures on top were synthesized on Au-catalyzed quartz substrates, via a vapor-solid process by a controlled vapor transport method. It was found that the Au catalyst and vapor-solid mechanism played an important role in the growth process and the growth phenomena in these structures were found to be in agreement with the preferential growth directions. The morphology and the structural evolution of the structure were successfully controlled and examined during the synthesis process. The controlled synthesis has made it possible for the In2O3 pyramid to be obtained either as an individual structure or as a cap on top of an In2O3 rod. In2O3 pyramids and In2O3 micro-rods were prepared at 900 and 1000 degrees C, respectively, and their electronic and room-temperature photoluminescence properties have been investigated. Current-voltage measurements were performed on a single In2O3 micro-rod in the temperature range 300-400 K and good quality ohmic contacts were obtained. Furthermore, the conductance of the In2O3 micro-rod has been found to increase slightly with increasing temperature, as revealed by temperature-dependent measurements. Photoluminescence measurements showed that In2O3 pyramids exhibited a UV luminescence band centered at 366 nm, while light emissions covering nearly the whole blue region have been observed in In2O3 micro-rods. The present work will enrich synthesis science and strongly indicates that processing conditions, as well as the morphology evolution control, are effective ways of fabricating In2O3-based tunable lightemitting devices. Furthermore, the faceted In2O3 microcrystal synthesized in this work may be promoted as pyramidal In2O3 microcavity, due to its unique shape that may allow multiple internal reflections of light at the titled pyramid facets.