[19p-436-1~17] 13.2 Exploratory Materials, Physical Properties, Devices

▼ [19p-436-2] Potential of BaSi₂ homojunction solar cells on a p⁺-BaSi₂/p⁺-Si tunnel junction

〇Tianguo Deng¹, Zhihao Xu¹, Yudai Yamashita¹, Komomo Kodama¹, Kaoru Toko¹, Takashi Suemasu¹ (1.Univ. Tsukuba)

Keywords:barium disilicide, tandem solar cells, tunnel junction

Barium disilicide (BaSi₂) shows great potential in solar cell applications as it has attractive features such as a suitable band gap, a large absorption coefficient and excellent minority-carrier properties. In our previous work, we successfully grew boron-doped p-BaSi₂ on n-Si(111) and Si(001) substrates with efficiencies (h) approaching 10%. In this study, prior to the formation of a BaSi₂-pn/Si-pn tandem solar cell, we aimed to form a p⁺-BaSi₂/p⁺-Si tunnel junction (TJ), which is necessary to make the electrical contact between BaSi₂-pn and Si-pn solar cells sufficiently small. We also simulated the h of a BaSi₂ homojunction solar cells on TJ, using automat for simulation of heterostructures (AFORS-HET). An h of 16.5% was simulated in a 500-nm-thick BaSi₂ homojunction solar cell with an open-circuit voltage (V_OC) of 0.76 V, a short-circuit density (J_SC) of 25.8 mA/cm² and a fill factor (FF) of 83.9%. The TJ properties were confirmed by experiment, and the tunnel current density reached 18.3 A/cm² at a bias voltage of 1.0 V, showing great potential for BaSi₂ homojunction solar cells on a TJ.