Hybrid photovoltaically active layer and method for forming such a layer
AssigneeSub-One Technology, Inc.
InventorsDeepak Upadhayaya, William J. Boardman, Charles Dornfest
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Abstract
A “hybrid” photovoltaically active layer is homogenous (in a direction parallel to the major surfaces of the layer) with respect to film constituents, but is non-homogenous with respect to photovoltaic properties. First regions exhibit high absorptivity, while second regions that are perpendicular to the major surfaces of the layer exhibit a higher carrier mobility. The method for forming the layer includes one or all of chemical vapor deposition, the hollow cathode effect, and high power DC pulsing.
Claims20
A photovoltaically active layer comprising:
- a single film of material which is responsive to incoming light to generate charge carriers, said film having first and second major surfaces and having first and second regions, in a lateral direction that is parallel to said first and second major surfaces said film being homogenous with respect to constituents of said film but being non-homogenous with respect to photovoltaic properties, said first regions being amorphous, said second regions having longer range order than said first regions and extending generally perpendicular to said major surfaces, said first regions thereby exhibiting a higher carrier generation rate than said second regions while said second regions exhibit a greater carrier lifetime than said first regions.
A method of forming a photovoltaically active layer comprising:
- forming a plasma within a deposition environment, said plasma including material to be deposited along a surface;
- and
- establishing deposition conditions such that said material is deposited as amorphous first regions and nanocrystalline second regions that have a lattice arrangement in general alignment with deposition growth of said photovoltaically active layer, wherein establishing said deposition conditions includes applying a pulsed bias so as to provide mobility to atoms of said material into locations that maintain said first and second regions as said deposition growth occurs.
A method of forming a solar cell having a sequence of layers to generate photo current in response to incident light, said method comprising:
- applying chemical vapor deposition techniques in forming said sequence of layers, including forming at least one layer in said sequence by:
- a) establishing a hollow cathode effect driving deposition of said at least one layer;
- and
- b) applying DC pulses such that said at least one layer is grown as a silicon-based layer having defined amorphous regions extending perpendicular to a growth direction and further having defined second regions extending parallel to said growth, said second regions establishing higher charge carrier lifetime regions relative to said amorphous regions.
Dependencies are inferred from the claim text.