High efficiency AlGaAs/Si tandem solar cell over 20%

✍ Scribed by Masayoshi Umeno; Toshimichi Kato; Takashi Egawa; Tetsuo Soga; Takashi Jimbo

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 714 KB
• Volume: 41-42
• Category: Article
• ISSN: 0927-0248
• DOI: 10.1016/0927-0248(95)00123-9

✦ Synopsis

A high efficiency A1GaAs/Si tandem solar cell has been fabricated by metal-organic chemical vapor deposition (MOCVD). It consists of a A10.15Gao.s5As top cell and a Si bottom cell. The crystalline quality of the A10asGa0.s5As heteroepitaxial layer grown on Si has been improved using a high temperature growth process (800°C) and thermal cycle annealing (300 ~ 900°C). The quantum efficiency of the Si bottom cell in the long wavelength region has been improved by back surface field. The conversion efficiencies of the tandem solar cell under AMO and 1 sun measurement conditions with 4-terminal and 2-terminal configuration are 20.0% and 19.0%, respectively. The conversion efficiencies of the tandem solar cell with graded band gap emitter AlxGal_xAs layer achieved 20.6% and 19.9% under the same condition with 4-terminal and 2-terminal configuration, respectively.