Solar cell structure with localized doping in cap layer
AssigneeEmcore Solar Power, Inc.
InventorsArthur Comfeld, Mark N. Stan, Paul R. Sharps
Life of this patent
Estimating the term…
Abstract
A solar cell includes a semiconductor substrate and a sequence of semiconductor layers disposed over the substrate. The sequence of semiconductor layers includes a semiconductor window layer. The solar cell also includes a semiconductor silicon-containing cap layer over the window layer. The cap layer is spatially separated from the window layer by a semiconductor barrier layer that either includes no silicon or has a silicon concentration that is significantly lower than the silicon concentration of the cap layer.
Claims30
A solar cell comprising:
- a semiconductor substrate;
- a sequence of semiconductor layers disposed over the substrate to form a plurality of subcell structures including a top subcell structure and a bottom subcell structure, wherein the top subcell structure includes a back surface field layer, a base layer directly over the back surface field layer, an emitter layer directly over the base layer, and a semiconductor window layer directly over the emitter layer;
- a semiconductor barrier layer over the window layer of the top subcell structure, wherein the semiconductor barrier layer does not constitute a base or emitter of any subcell structure;
- and
- a semiconductor silicon-containing cap layer over the barrier layer, wherein the semiconductor barrier layer either includes no silicon or has a silicon concentration that is at least 50% lower than the silicon concentration of the cap layer.
A method of fabricating a solar cell comprising:
- depositing a sequence of semiconductor layers to form a solar cell structure over a semiconductor substrate, wherein the sequence of semiconductor layers includes a base layer, an emitter layer directly over the base layer, and a window layer directly over the emitter layer;
- depositing a semiconductor barrier layer directly over the window layer;
- and
- depositing a semiconductor silicon-containing cap layer directly over the barrier layer, wherein the barrier layer either includes no silicon or has a silicon concentration that is at least 50% lower than the silicon concentration of the cap layer.
A solar cell comprising:
- a semiconductor substrate;
- a sequence of semiconductor layers disposed over the substrate, wherein the sequence of semiconductor layers includes a top subcell structure and a bottom subcell structure, and wherein the top subcell structure-includes a base layer, an emitter layer directly over the base layer, and a window layer directly over the emitter layer;
- and
- a semiconductor silicon-containing cap layer over the window layer of the top subcell structure, wherein the cap layer is spatially separated from the window layer of the top subcell structure by a semiconductor barrier layer to prevent diffusion of silicon from the cap layer into the window layer.
A method of fabricating a solar cell comprising:
- depositing a sequence of semiconductor layers including a top subcell structure and a bottom subcell structure to form a solar cell structure over a semiconductor substrate, wherein the top subcell structure includes a base layer, an emitter layer directly over the base layer, and a window layer directly over the emitter layer;
- depositing a semiconductor barrier layer directly over the window layer;
- and
- depositing a semiconductor silicon-containing cap layer over the barrier layer, wherein the barrier layer prevents diffusion of silicon from the cap layer into the window layer of the top subcell structure.
Dependencies are inferred from the claim text.