Low-cost multi-junction solar cells and methods for their production

US7951640B2 · kind B2 · utility

Assignee

• SUNPREME · KY

Inventor

• Ashok Sinha · Palo Alto, US

Key dates

• Filing date: Dec 2, 2009
• Grant date: May 31, 2011
• Expiry date: Dec 2, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P70/50

Abstract

Solar cells fabricated without gasification of metallurgical-grade silicon. The substrates are prepared by: melting metallurgical grade silicon in a furnace; solidifying the melted metallurgical grade silicon into an ingot; slicing the ingot to obtain a plurality of wafers; polishing and cleaning each wafer; depositing aluminum layer on backside of each wafer; depositing a layer of hydrogenated silicon nitride on front surface of each wafer; annealing the wafers at elevated temperature; removing the hydrogenated silicon nitride; and, removing the aluminum layer. The front surface may be textured prior to forming the solar cell. The solar cell structure comprises a metallurgical grade doped silicon substrate and a thin-film structure formed over the substrate to form a p-i-n junction with the substrate. The substrate may be doped p-type, and the thin film structure may be an intrinsic amorphous layer formed over the substrate and an n-type amorphous layer formed over the intrinsic layer.