Patent ID: 11916159
Assignee: SOLAERO TECHNOLOGIES CORP
Field: Semiconductors (Electrical engineering)
Classification: CPC H  C  Y | IPC H

Claim 18:
19. A method as defined in claim 14, further comprising:
a distributed Bragg reflector (DBR) layer disposed adjacent to and beneath the third solar subcell and arranged so that light can enter and pass through the third solar subcell and at least a portion of which can be reflected back into the third solar subcell by the DBR layer, wherein the distributed Bragg reflector layer is composed of a plurality of alternating layers of lattice matched materials with discontinuities in their respective indices of refraction, wherein the difference in refractive indices between alternating layers is maximized in order to minimize the number of periods required to achieve a given reflectivity, and the thickness and refractive index of each period determines the stop band and its limiting wavelength, and wherein the DBR layer includes a first DBR layer composed of a plurality of p-type AlxGa1-xAs layers, and a second DBR layer disposed over the first DBR layer and composed of a plurality of p-type AlyGa1-yAs layers, where 0<x<1, 0<y<1, and y is greater than x; and an intermediate layer disposed between the DBR layer and the growth substrate, wherein the intermediate layer is compositionally step-graded to lattice match DBR layer on one side and the growth substrate on the other side, and is composed of any of the As, P, N, Sb based III-V compound semiconductors subject to the constraints of having the in-plane lattice parameter greater than or equal to that of the DBR layer and less than or equal to that of the growth substrate.