Synthesis of SnO2 nanowires using thermal chemical vapor deposition with SnO powder and their application as self-powered ultraviolet photodetectors

We report on the performance of self-powered ultraviolet (UV) photodetectors composed of SnO2 nanowire (NW) networks. SnO2 NWs with a length of several hundred micrometers can be synthesized by thermal chemical vapor deposition (CVD) using SnO powder as the raw material, which has the advantages of a low process temperature and no requirement for a reducing agent. Based on the characterization results obtained through synchrotron X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM), we determined the growth behavior of SnO2 NWs via a vapor-liquid-solid mechanism with Au nanoparticles. The NW growth switched from an initial in-plane growth to subsequent vertical growth, forming NW cotton. This was started at a process temperature of 600 degrees C and optimized at 800 degrees C. Moreover, the XRD and TEM results indicate that the NWs mainly grew in the form of SnO2, although the formation of SnO NWs was also possible. Metal SnO2 NW metal type photodetectors were fabricated, and their photoresponsivity to UV light in the range from 200 to 400 nm was investigated. The device exhibited a photo-to-dark current ratio of similar to 2.17 x 106 at an applied bias of 10 V and 254 nm UV exposure. A maximum responsivity of about 1100 A/W was estimated at a wavelength of 270 nm, and the cutoff edge wavelength appeared around 350 nm. In particular, the self-powered photoresponse at nominal zero bias was similar to 1.23 nA. The results of this study support the idea that SnO2 NWs are promising candidates for self-powered deep-UV photodetectors and that thermal CVD using SnO powder is suitable for synthesizing SnO2 NWs at temperatures as low as 700 degrees C.

Automated summary

We present the performance of self-powered UV photodetectors composed of SnO2 nanowire networks. The synthesis of SnO2 nanowires with a length of several hundred micrometers was achieved using thermal chemical vapor deposition (CVD) at low process temperatures without a reducing agent. The growth behavior of the nanowires was determined through characterization methods, and the device exhibited a high photo-to-dark current ratio and responsivity to UV light in the deep UV range. The results show that SnO2 nanowires have great potential for self-powered UV photodetectors and can be synthesized at low temperatures using SnO powder.