[20a-PA4-1~12] 13.2 Exploratory Materials, Physical Properties, Devices

▲ [20a-PA4-2] Investigation 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 Alpes, 3.Kyushu Inst. Tech.)

Keywords:Barium disilicide, photoluminescence

Barium disilicide (BaSi₂) shows great potential in solar cell applications as it has attractive features such as a suitable band gap (E_g=1,3 eV), a high absorption coefficient (α exceeding 3 × 10⁴ cm^-1), a long minority-carrier lifetime (τ ~ 10 µs), and a large minority-carrier diffusion length (L ~ 10 µm). However, undoped-BaSi₂ contain point defects which can be detected by deep level transient spectroscopy. 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 ratio of Ba deposition rate to the Si deposition rate (R_Ba/R_Si) has an impact on carrier concentration and photoresponsivity of BaSi₂. Therefore, we decided to analyze samples with various values of R_Ba/R_Si 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.