TEMPERATURE-DEPENDENCE OF THE IDEALITY FACTOR OF BA1-XKXBIO3 NB-DOPEDSRTIO3 ALL-OXIDE-TYPE SCHOTTKY JUNCTIONS

Current-voltage measurements were performed on Ba1-xKxBiO3/Nb-doped Sr TiO3 (BKBO/STO:Nb) all-oxide-type Schottky junctions in the temperatur e range of 30 to 300 K. The relative permittivity epsilon(r)(E, T) of undoped SrTiO3(110) was measured as a function of both temperature and electric field. An anomalous increase in ideality factor n(T) and dec rease in zero-bias barrier height Phi(b0)(T) with decreasing temperatu re were observed and were analyzed using the interfacial layer model w ith a thin insulating interfacial layer present between metal contact (BKBO) and semiconductor interface (STO:Nb), The increase in n(T) at l ow temperature can be explained by taking into account the temperature dependence of the permittivity of the depletion layer (STO:Nb). The e ffect of the electric field dependence of the permittivity of STO:Nb o n n(T) is also discussed using an approximate electric field dependenc e, epsilon(r)(T, E) = b/(a + E-2)(1/2), where a and b are constants.