Enhancing the low temperature hydrogen sensitivity of nanocrystalline SnO2 as a function of trivalent dopants

Abstract

The effect of different indium doping concentrations on the room temperature hydrogen sensitivity of nano-SnO2 is investigated. The role of calcination temperature on the surface morphology, phase transformation, and subsequent impact on the gas sensing behavior of nanocrystalline doped SnO2 is presented. Differences in grain growth with varying doping amount give an explanation for enhanced sensing that is not always so obvious. Variation in the charge carrier density for indium doped nanocrystalline SnO2 is calculated as a function of indium concentration in the tin oxide lattice structure. The charge carrier density is correlated to the involved surface species of doped nanocrystalline SnO2 upon hydrogen gas exposure using Fourier transform infrared spectroscopy