Room-temperature epitaxy of indium tin oxide (ITO) thin films was achieved on Si(I 11) substrates with an epitaxial CeO2 ultrathin buffer using a pulsed laser deposition technique. The epitaxial CeO, buffer layer was also grown at room temperature. Reflection high-energy electron diffraction and pole figure X-ray diffraction analyses confirmed the formation of a double heteroepitaxial structure of ITO(111)/CeO2(111)/Si(111) with the epitaxial relationship Of [-110](110)//[-110](CeO2H)//[1-10](Si). The junction of [ITO: 100 nm thick/CeO2: 3 nm thick/p-Si(111)] fabricated at room temperature exhibited solar cell properties.