Epitaxial growth of metastable c-plane rhombohedral indium tin oxide using mist chemical vapor deposition

Corundum structured metastable rhombohedral indium tin oxide (rh-ITO), which is known to grow as thin films, has attracted significant research interest; however, its properties, based on the Sn concentration, have not been evaluated in detail thus far. Herein, rh-ITO thin films comprising different Sn concentrations were grown on c-plane alpha-Al2O3 substrates with alpha-Ga2O3 buffer layers using the mist chemical vapor deposition method, and their properties were investigated. X-ray diffraction analysis revealed that c-plane rh-ITO thin films grew epitaxially at Sn concentrations of 0-10 at.%. The lowest thin film resistivity is determined to be approximately 3.3 x 10(-4) Omega cm, which is sufficiently low for a transparent conductive oxide. The carrier concentration and mobility exhibited by the rh-ITO films were consistent with those of typical single-crystalline ITO films, which exhibited the most stable phase. The rh-ITO thin films exhibited high transmittance in the visible light region, and the absorption edge was blue-shifted with the increasing carrier concentration. This study demonstrates that rh-ITO can be used as a new transparent conductive oxide material for diverse applications.

Automated summary

In this study, rh-ITO thin films with different Sn concentrations were successfully grown using the mist chemical vapor deposition method. The films exhibited low resistivity, high transmittance, and can be used as transparent conductive oxide materials.