Relationship of the electric potential inside the nano crystallite with the chemisorbed gas molecules at metal oxide semiconductor surface and its effect on gas sensor response

Abstract

The metal oxide semiconductors surface exhibit great gas sensing response when the size of the grains becomes much smaller i.e. in the range of debye length. In the presented study, the effect of crystal size and surface states has been studied on gas sensing properties for cylindrical shaped nanostructures of metal oxide semiconductors. To calculate the grain potential Poisson’s equation coupled with electroneutrality condition in cylindrical shaped nanostructures has been solved. The shape of the potential profile inside the nanograins has been calculated as a function of available surface states, surface temperature and occupied surface states. Eventually, the sensitivity of the gas sensor has been simulated and compared for different sizes of nanocrystals.