Title :
High efficiency AlGaAs/Si tandem solar cell over 20%
Author :
Umeno, Masayoshi ; Kato, Toshimich ; Yang, Mingju ; Azuma, Yutaka ; Soga, Tetsuo ; Jimbo, Takashi
Author_Institution :
Dept. of Electr. & Comput. Eng., Nagoya Inst. of Technol., Japan
Abstract :
A high-efficiency AlGaAs/Si tandem solar cell is fabricated by metal-organic chemical vapor deposition (MOCVD). It consists of a Al0.15Ga0.85As top cell and a Si bottom cell. The crystalline quality of the Al0.15Ga0.85As heteroepitaxial layer grown on Si is improved using a high-temperature growth process (800°C) and thermal cycle annealings (300~900°C). The quantum efficiency of the Si bottom cell in the long wavelength region is 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 AlxGa1-xAs layer achieved 20.6% and 19.9% under same condition with 4-terminal and 2-terminal configuration, respectively
Keywords :
CVD coatings; III-V semiconductors; aluminium compounds; annealing; chemical vapour deposition; elemental semiconductors; gallium arsenide; p-n heterojunctions; semiconductor device testing; semiconductor growth; semiconductor thin films; silicon; solar cells; 19 percent; 19.9 percent; 20 percent; 20.6 percent; 300 to 900 C; 800 C; Al0.15Ga0.85As; AlGaAs-Si; AlGaAs/Si tandem solar cell; MOCVD; back surface field; crystalline semiconductor quality; graded-band-gap emitter layer; heteroepitaxial layer growth; high-temperature growth process; long wavelength region; metal-organic chemical vapor deposition; quantum efficiency; thermal cycle annealing; Annealing; Chemical vapor deposition; Crystallization; Electrodes; Gallium arsenide; Gold; MOCVD; Photonic band gap; Photovoltaic cells; Substrates;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.520541
