Patent ID: 8853529

Claim:
A structure comprising: a germanium substrate; a buffer region formed directly on the germanium substrate, the buffer region including a highly doped, electrically conductive layer comprising gallium arsenide, and a solar cell structure in inverted order on the buffer region, the solar cell structure including an absorbing layer comprising gallium arsenide, an emitter layer, a window layer adjoining and directly contacting the highly doped, electrically conductive layer of the buffer region and the emitter layer, the emitter and window layers being formed between the buffer region and the absorbing layer, and a back surface field layer formed on a side of the absorbing layer opposite from the substrate, wherein the highly doped, electrically conductive layer is configured to be functional as a buffer layer between the germanium substrate and the solar cell structure, thereby preventing antiphase defects, and is further configured for employment as an ohmic contact layer for the solar cell structure.