Detection, identification, and impact of native point defects on conduction in ITO thin films

We used depth-resolved cathodoluminescence spectroscopy and van-der-Pauw-Hall measurements to determine the effects of molecular beam epitaxy growth and processing conditions on native point defects in indium tin oxide (ITO). The near-nanometer depth resolution of this optical technique enabled us to identify spectral changes associated with removing or creating these defects, leading to the identification of oxygen-related defects in the indium tin oxide bandgap. The combined near-surface detection and processing of ITO together with their correlation with Hall effect mobility indicates an avenue for identifying the physical nature and reducing the density of specific native point defects to increase the free carrier concentration and conductivity of ultrathin ITO.