IN-SITU FORMATION OF P-N-JUNCTIONS IN SEMICONDUCTING TIO2

Application of small voltages in the range from 0.5 V to 1 V to an ori ginally homogeneously Fe-doped (0.5 mol-%) TiO2 semiconductor at tempe ratures between 700-degrees-C and 750-degrees-C caused the formation o f a p-n junction within the sample. This is indicated by a change of t he U-I characteristics from a symmetrical to a diode type behavior. By inversion of the polarity of the applied voltage, the p-n junction co uld be removed. This process is completely reversible. The results are explained by an asymmetric change in the concentration of lattice def ects, which act as dopants in addition to the extrinsic dopants, cause d by the application of the voltage to the sample.