The metamorphic multi junction GaAs solar cell comprises a top cell mainly composed of GaInP, a middle cell mainly composed of InGaAs and a bottom cell mainly composed of Ge. AlInP (P +) / AlGaAs (P + +) - GaInP (n + +) / AlInP (n +) or AlGaInP (P +) / AlGaAs (P + +) - GaInP (n + +) / AlInP (n +) are arranged between the top cell and the middle cell Tunnel junction connection structure. The multi junction GaAs solar cell of the invention adopts the above tunnel junction connection structure, which can not only significantly reduce the reflection of incident light, improve the current density of the medium cell, but also improve the conversion efficiency of the three junction cell.
Metamorphic multijunction solar cell is multiple p-n junctions, which are made of different semiconductor materials. The p-n junction of each material will generate current according to different wavelengths of light. The use of a variety of semiconductor materials allows absorption of a wider wavelength range, thereby improving the conversion efficiency of solar energy to electric energy.
The maximum theoretical efficiency of traditional single junction battery is 33.16%. Theoretically, in highly concentrated sunlight, an infinite number of junctions will have a limit efficiency of 86.8%.So the multijunction solar cell is better than single junction cell.