Patent ID: 9231147
Filing Date: 2016-01-05
CPC Classification: H01L,Y02E

Claim Text:
1. A method of forming a multijunction solar cell comprising: forming a bottom subcell having a bandgap in the range of 0.8 to 1.2 eV; forming a heterojunction middle subcell having a base and emitter, a bandgap greater than the bandgap of the bottom subcell and less than about 1.5 eV, and being disposed over and being lattice mismatched to the bottom subcell; forming a continuously-graded interlayer composed of InGaAlAs and having a bandgap that remains about constant between the middle and bottom subcells by identifying a set of compositions of the formula (In forming a homojunction top subcell having a base and emitter and being disposed over and being lattice matched to the middle subcell, wherein said graded interlayer is compositionally graded to lattice match the middle subcell at one side and the bottom subcell at an opposing side, and wherein forming the graded interlayer further comprises providing a metal organic chemical vapor deposition (MOCVD) system configured to independently control the flow of source gases trimethylindium (InMe