[10a-PB2-1~18] 13.2 探索的材料物性・基礎物性

▲ [10a-PB2-10] Study of the origin of defect levels in undoped-BaSi2 epitaxial films by PL measurement

〇Louise Benincasa^1,2、Hirofumi Hoshida³、Tianguo Deng¹、Takuma Sato^1,2、Kaoru Toko¹、Yoshikazu Terai³、Takashi Suemasu¹ (1.Univ. Tsukuba、2.Univ. Grenoble Aples、3.Kyushu Inst. Tech.)

キーワード：Barium disilicide, Photoluminecsence, Defects

Barium disilicide (BaSi2) shows great potential in solar cell applications as it has attractive features such as a suitable band gap (Eg=1,3 eV), a high absorption coefficient (α exceeding 3 × 104 cm-1), a long minoritycarrier lifetime (τ ~ 10 μs), and a large minority-carrier diffusion length (L ~ 10 μm) [1]. However, undopedBaSi2 contains point defects which introduce localized states within the bandgap. In this study, the goal is to evaluate the defects properties such as the energy level or the density. Our previous research shows that the PL was ascribed to the transition of electrons between localized states. As the ratio of Ba deposition rate to the Si deposition rate (RBa/RSi) has an impact on carrier concentration and photoresponsivity of BaSi2[2], we decided to analyze samples with various values of RBa/RSi by photoluminescence (PL). In this way, we will be able to have a better understanding about the origin of these defects and find a way to suppress or reduce them.