Abstract
This study reports successful synthesis of non-stoichiometric single-crystal W <sub>18</sub> O <sub>49-x</sub> S <sub>x</sub> nanowires for photosensors with a high absorption rate (>83%) across a wide spectrum (300-2000 nm), a high internal gain (G = 10 <sup>6</sup> -10 <sup>7</sup> ) and a relatively fast response time (approximately 1-3 s). In addition, the correlation between the photoconductivity gain (G) and the surface-to-volume ratio of non-stoichiometric single-crystal W <sub>18</sub> O <sub>49-x</sub> S <sub>x</sub> nanowires was studied. The surface-to-volume ratio and non-stoichiometric material of W <sub>18</sub> O <sub>49-x</sub> S <sub>x</sub> contributed to the photoconductivity gain; hence, the nanowires are favorable for photosensor devices. The wide spectrum obtained also suggests their extensive applications in numerous fields.