Effects of crystalline structural transition on electronic-band structure of chromium-doped indium oxide

The electronic-band structure parameters of chromium-doped indium oxide films with crystalline structural transition were determined by fitting the dielectric functions of Drude and Adachi's model to near-normal reflectance spectra. The evaluated optical bandgap shows a maximum at an intermediate state and decreases respectively toward highly and less ideally crystallized states. We explain this phenomenon by combining the effect of intrinsic bandgap narrowing with the Burstein–Moss shift, both due to the crystalline structural transition. This work provides important insights into electronic-band structures of less ideally structured materials.