RECTIFYING CURRENT-VOLTAGE CHARACTERISTICS IN YBA2CU3O7-X/NDGAO3/N-SRTIO3 DIODES

Rectifying current-voltage characteristics were analyzed for YBa2Cu3O7-x/NdGaO3/n-SrTiO3 diodes made by depositing NdGaO3 barriers and YBa2Cu3O7-x films on Nb-doped SrTiO3 substrates using KrF excimer laser ablation. The diode capacitance measured at 10 kHz indicated that the relative permittivity of the NdGaO3 barrier was 13 at 10 K. Diodes exhibited rectifying current-voltage characteristics where they conducted better for positive voltages on the n-SrTiO3 than for negative voltages. The current density of the diode having a 5-nm-thick NdGaO3 barrier biased around 1 V on the n-type SrTiO3 was 0.2 A/cm2 at 30 K. This current density is at least six orders of magnitude higher than that obtained for diodes with YBa2Cu3O7-x electrodes directly placed on n-SrTiO3 Substrates.