Observation of deviation of electronic behaviour of indium tin oxide film at grain boundary using Scanning Tunneling Microscope

Abstract

Scanning Tunneling Microscopy and Spectroscopy investigations have been carried out on electron beam deposited indium tin oxide films. The STM images reveal a rather smooth surface, which appears to have been formed due to the coalescence of islands with different shapes. The spectroscopic data, in general, exhibit characteristics typical of metal-insulator-semiconductor structures, with a heavily doped semiconductor. From the I-V curves, a band gap of ≈3.5 eV is obtained, which is very close to the bulk value. The I-V studies at some grain boundary interfaces suggest the presence of regions showing electronic characteristics, that differ significantly from what is observed on the rest of the film surface.