GAASP TOP SOLAR CELL OF THREE-TERMINAL GAASP/SIGE ON SI TANDEM SOLAR CELLS

摘要

Integrating a high voltage solar cell on a crystalline silicon solar cell can lead to a 40% increase in efficiency for a silicon-based solar cell. GaAsP with its wide band gap and good diode performance is an excellent top cell candidate on this silicon-based tandem solar cell. A SiGe buffer grown between GaAsP and Si leads to lattice-matching. SiGe can also be designed as a bottom cell to increase power output. This 3-terminal approach splits the stack into two cells and facilitates individual analysis by adding middle metal contacts between top GaAsP and bottom SiGe solar cells. This paper describes design, fabrication and improvement of a GaAsP top cell in this 3-terminal GaAsP/SiGe tandem solar cell on silicon. Initial efficiency of GaAsP top cell with AR coating has achieved 18.4%. Bandgap-voltage offset under open circuit condition (W_(oc)) achieved 0.48V. With improved optics and fill factor, the efficiency of this GaAsP top cell is expected to be more than 22%.