[13a-N203-1~7] 6.4 Thin films and New materials

△ [13a-N203-3] Epitaxial thin-film growth and optical property characterization of a layered compound BiI₃

〇(M1)Takahiro Yasuami¹, Masao Nakamura², Soutarou Inagaki¹, Shingo Toyoda², Naoki Ogawa^1,2, Yoshinori Tokura^1,2,3, Masashi Kawasaki^1,2 (1.Univ. of Tokyo, 2.RIKEN-CEMS, 3.Tokyo College)

Keywords:thin film, molecular beam epitaxy, exciton

BiI₃ is a layered compound exhibiting giant excitonic responses and is also expected as a photovoltaic material. However, the growth of high-quality thin has never been achieved so far. In this study, we fabricated thin films of BiI₃ on sapphire substrate by molecular beam epitaxy. We successfully grew perfectly c-axis oriented films with atomic flatness by introducing a thin buffer layer formed at a low temprature. Absorption spectra measured at low temprature shows strong and sharp excitonic transitions similar to those of bulk single crystals, indicating that the fabricated film has high crystalinity comparable to bulk single crystals