INTERFACE AND SURFACE STATISTICS FOR A SCHOTTKY-BARRIER GAS SENSOR

A consistent two-dimensional theory of the field effect at the three-phase boundary is developed. The two-dimensional Poisson equation is approximately solved by a superposition of the one-dimensional Schottky potentials taking into account a rigorous statistical treatment of chemisorbed surface states in the framework of the Volkenstein model. For numerical demonstration, a single microcontacted grain boundary is considered, calculating the I-U characteristics for a Schottky-barrier gas sensor. The main features of the proposed microscopic model are: the recharging of surface and interface states, the x-dependent surface charge density, which exhibits a minimum at the three-phase boundary. and the non-ideality of the I-U characteristics.