UV and Oxygen Sensing Properties and Space Charge Limited Transport of Sonochemically Grown ZnO Nanowires

We report on a room ambient sonochemical process to synthesize Zinc Oxide (ZnO) nanowires for fabricating UV photodetectors and gas sensors on an amorphous substrate. We investigated the conduction properties and the adsorption mechanism at the nanowire surface with and without UV exposure with variation in atmospheric pressure. Optical spectroscopy, scanning electron microscopy (SEM) and current–voltage measurements were used to characterize these samples. The results show that highly dense nanowires can be grown with the use of ultrasound at ambient conditions without a seeding layer of ZnO. We observe non-linear space charge limited current (SCLC) in the nanowires which is attributed to the readily incorporated traps during the sonochemical growth. UV photodetectors and gas sensors have been shown as practical applications of these nanowires grown with this simple method.