18:30 〜 18:45
▲ [19p-436-17] Significant photoresponsivity improvement of BaSi2 films by atomic hydrogen irradiation using radio-frequency plasma
キーワード：Photoresponsivity
Introduction
Semiconducting material BaSi2 is a good candidate for the solar cell application due to several advantages such as a suitable band gap of 1.3 eV, a large absorption coefficient of 3 × 104 cm-1 at 1.5 eV, exceeding those of CIGS [1], and a large minority-carrier diffusion length of ca. 10 µm [2]. On the surface of BaSi2, pure amorphous Si (a-Si) is used to prevent oxidation of BaSi2. However, a-Si is a long-range disordered material and contains a lot of dangling bonds. As a result, the dangling bonds act as defects and hinder photogenerated carriers to reach the surface electrodes. Furthermore, first-principle calculation predicts Si vacancies to be most likely to exist as a native point defect in BaSi2 and induce localized states within the band gap [3]. In our previous work [4], we have achieved the photoresponsivity enhancement by a fact of 4 for a 500-nm-thick BaSi2 film capped with a 3-nm-thick a-Si:H layer compared to that capped with a pure a-Si layer. In this work, we investigated the influence of atomic H supply on the photoresponsivity of BaSi2 films.
Semiconducting material BaSi2 is a good candidate for the solar cell application due to several advantages such as a suitable band gap of 1.3 eV, a large absorption coefficient of 3 × 104 cm-1 at 1.5 eV, exceeding those of CIGS [1], and a large minority-carrier diffusion length of ca. 10 µm [2]. On the surface of BaSi2, pure amorphous Si (a-Si) is used to prevent oxidation of BaSi2. However, a-Si is a long-range disordered material and contains a lot of dangling bonds. As a result, the dangling bonds act as defects and hinder photogenerated carriers to reach the surface electrodes. Furthermore, first-principle calculation predicts Si vacancies to be most likely to exist as a native point defect in BaSi2 and induce localized states within the band gap [3]. In our previous work [4], we have achieved the photoresponsivity enhancement by a fact of 4 for a 500-nm-thick BaSi2 film capped with a 3-nm-thick a-Si:H layer compared to that capped with a pure a-Si layer. In this work, we investigated the influence of atomic H supply on the photoresponsivity of BaSi2 films.