[16a-P3-1~11] 13.2 Exploratory Materials, Physical Properties, Devices

▲ [16a-P3-5] Minority-carrier lifetime in B-doped BaSi₂ epitaxial films

〇(M1)Emha Bayu Miftahullatif¹, Cham Thi Trinh², Takabe Ryota¹, Yachi Suguru¹, Toko Kaoru¹, Usami Noritaka², Suemasu Takashi¹ (1.Univ. of Tsukuba, 2.Nagoya Univ)

Keywords:solar cell, silicide, semiconductor

BaSi₂ is attracting attention as a future absorber-layer material for earth abundant thin film solar cell. It has an indirect band gap of approximately 1.3 eV, matching the solar spectrum, and has large absorption coefficients, which is 30 times larger than that of crystalline silicon [1,2]. Recently we have fabricated n-Si/B-doped p-BaSi₂ heterojunction solar cell that achieved a conversion efficiency of 9.0% [3]. In the work mentioned, B-doped p-BaSi₂ (p = 2.2 × 10¹⁸ cm^-3) with an optimum thickness of 20 nm acts as a hole transport layer. The deterioration of in thicker p-BaSi₂ layer are suspected due to the small minority-carrier diffusion length of p-BaSi₂ layer. In order to leverage p-BaSi₂’s potential as absorption layer, we need to increase the thickness of p-BaSi₂ layer by employing those with excellent minority-carrier lifetime. In this work we performed minority-carrier lifetime measurement by microwave-detected photoconductivity decay (μ-PCD), of B-doped p-BaSi₂ with various hole concentrations in the pursuit of p-BaSi₂ with the most excellent minority carrier lifetime.