Hall effect measurements to determine surface electronic properties of semiconductor epitaxial films

Abstract

It is shown that Hall effect measurements combined with near surface charge neutrality can self-consistently determine surface electronic properties such as the surface potential ψs and the density of states NssD,A (m−2) of surface defect levels of energy EssD,A in the semiconductor gap. A method is proposed to achieve these goals, and since the present approach involves approximations, it has limitations, which are critically evaluated. Following the development of the proposed methodology, applications to n- and p-type homoepitaxial InP films grown on semi-insulating InP:Fe (001) substrates are implemented. The ψs and NssD,A results obtained have implications on the temperature dependence of the work function and ionization potential of a free surface. They also indicate that this approach warrants further development since, as is common with most electrical measurements, their sensitivity has the potential to determine these properties with high accuracy.