An n- to p-type conductivity transition induced by oxygen adsorption on α-Fe2O3

The simultaneous measurements of conductance and work function changes induced by gaseous ambient have been performed on alpha-Fe2O3 thick film polycrystalline samples kept at 280 degreesC and exposed to different gaseous atmospheres. The switching from n- to p-type conductivity on alpha-Fe2O3 is shown to have an electronic origin, which is due to the oxygen adsorption and formation of a surface inversion layer and, therefore, to the inversion of the surface conduction type. The modeling of the n-p switching is described in terms of conductance dependence on the band bending induced by gaseous ambient. (C) 2004 American Institute of Physics.