Thermal Ge heterojunction photovoltaic cell substrate

The present invention relates to a heat Ge substrate heterojunction photovoltaic cell comprising a base region of a Ge substrate, a Ge substrate are sequentially grown from bottom to top above the emitter region, the upper electrode contact layer and the upper electrode, made of a Ge substrate below lower electrode, Ge substrate, a narrower band gap p-Ge layer; emitter region is relatively wide band gap n-GaxInyP layer. As a result of the present invention having the ratio of Ga and In wide band gap can be precisely regulated layer as a n-GaxInyP emitting region, using the substrate p-Ge as the band gap narrower base region, forming a base region and emitter region exact lattice matched heterostructure, reducing GaxInyP / Ge interface recombination, the wide band gap emitter region to reduce absorption of light emission and absorption of light increases the base region, thereby reducing the photo-generated carriers in the n type emitter region and the surface of the composite, to improve the collection efficiency of the photogenerated carriers, effectively improving the photoelectric conversion efficiency of the battery.