Investigation of the Optical Properties of Nanostructured Transparent Conducting Oxides

Abstract

Transparent conducting oxides (TCOs) usually have high conductivity and transparency in the visible range and have been widely used in daily life. Recently, TCOs have attracted great interest due to their potential applications in various new optical and electrical devices (flat-panel displays, energy efficient windows, etc.). Nanostructured TCOs can induce new size related properties, for example, when sizes of TCOs are controlled at the nanometer scale, various defects can introduce different defect-related optical emissions. These new nanostructured TCOs combining traditional and new size dependent properties may be used for construction of next generation optical devices. To investigate the optical properties of TCOs at nanoscale, in this thesis, several new kinds of colloidal nanocrystals (NCs) of TCOs have been synthesized and their optical emission and transparency have been explored. The first part of my work focuses on ITO (indium tin oxide) NCs demonstrates phase and size dependence of surface plasmon absorption in the near infrared region. The second part of the thesis describes colloidal synthesis of γ-Ga2O3 with size tunable photoluminescence, further study reveals that the photoluminescence is defect related and can be tuned by changing the defect concentration. In the last part of my study, I develop a methodology for lanthanide doped γ-phase Ga2O3 NCs and reveal tunable chromaticity of the lanthanide doped NCs.