Room-temperature H2S gas sensing at ppb level by single crystal In2O3 whiskers

In2O3 whiskers and bipyramidal nano-crystals were prepared by a carbothermal method. These were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), photoluminescence and Raman spectroscopy. These were studied for application to sensing of H2S gas. The single crystal whiskers were found to be sensitive to as low as 200 ppb of H2S gas at room temperature and showed saturation in response at 10 ppm. On the other hand, the films made of bipyramids were less sensitive to H2S gas and the response was found to be a nearly linear function of concentration in a concentration range of 10–80 ppm.