Domain structure and optical property of epitaxial indium oxide film deposited on MgO(100) substrate

► A clear epitaxial relationship of In2O3(111)||MgO(100) has been proposed. ► A four-domain structure has been found inside the In2O3 epitaxial film. ► A theoretical model for the epitaxial growth mechanism has been proposed. ► The In2O3 film has an excellent optical transparency and a band gap of 3.76 eV.