[18p-Z15-1~15] 6.4 Thin films and New materials

△ [18p-Z15-5] Free-exciton emission in heteroepitaxially-grown CuI single-crystalline films

〇(M2)Sotaro Inagaki¹, Masao Nakamura², Yoshihiro Okamura¹, Makiko Ogino¹, Yotaro Takahashi^1,2, Licong Peng², Xiuzhen Yu², Yoshinori Tokura^1,2,3, Masashi Kawasaki^1,2 (1.Univ. of Tokyo, 2.RIKEN-CEMS, 3.Tokyo College)

Keywords:wide gap semiconductor, crystallinity, exciton

CuI is a wide-bandgap semiconductor of superior excitonic properties. However, there has been no report demonstrating a fabrication of single-crystalline films. In this study, we employed InAs as a substrate with a good lattice matching with CuI. We could successfully grow single-crystalline films with high lattice coherence exceeding that in bulk single crystals and atomically-flat surfaces. Photoluminescence spectra exhibit quite sharp free-exciton emission, owing to the dramatic suppression of defect density.