Photo- and Electron-Beam-Induced Currents from Epitaxial YBa2Cu3Oy Metal-Insulator-Superconductor (MIS) Structure in the Normal State

Abstract
We present the first report of observation of photoinduced and electron-beam-induced short-circuit currents across the Al/(100)SrTiO3/(001)YBa2Cu3O y metal-insulator-superconductor (MIS) structure in the normal state. Observed current flow is an indication of downward band bending of the YBa2Cu3O y surface layer at the MIS interface, in accordance with the prediction by Hirano et al. based on its large work-function value (Jpn. J. Appl. Phys. 31 (1992) L1345). The electron-beam-induced current (EBIC) image revealed structural defects at the interface. From this image, diffusion length in the (001)YBa2Cu3O y layer was roughly estimated as 0.1∼0.2 µm.