Optical Characterization of Structural Quality in the Formation of In2O3 Thin-Film Nanostructures

We report on optical examination of structural properties of cubic-In2O3 (c-In2O3) degenerate-semiconducting-oxide thin-film nanostructures grown On Si (100) substrates using vapor transport method driven with vapor liquid solid mechanism. Two different types of dense (A) and loose (B) c-In2O3 thin-film nanorods have been, respectively, characterized by photoluminescence (PL), time resolved photoluminescence (TRPL), thermoreflectance (TR), and Hall arid resistivity measurements. Strong excitonic emissions detected from the PL results of the A and B samples identify the high-crystalline quality of the arrow-type-c-In2O3 nanorods. Theoretical modeling fits on the TRPL results of the A and B samples characterize and identify defect mechanisms of the nanostfuctured thin films. Near-band-edge and above-band-edge transitions such as excitons, direct band gap, and Burstein Moss shift (above direct gap) in the degenerate A and B c-In2O3 have also been,detected by TR measurement. Field-emission scanning electron microscopy and field-emission transmission electron microscopy have been implemented to facilitate the observed optical measurement results of the c-In2O3. All experimental analyses show that the TR, PL, and TRPL measurements are powerful techniques for optical characterization of structure and optodectronics properties of the c-In2O3 degenerate nanostructured thin film available for transparent optoelectronics use.