Cadmium-free junction fabrication process for CuInSe.sub.2 thin film solar cells

Patent · 01 January 1999

OSTI ID:872498

Ramanathan, Kannan V ^[1]; Contreras, Miguel A ^[2]; Bhattacharya, Raghu N ^[3]; Keane, James ^[1]; Noufi, Rommel ^[2]

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1. Lakewood, CA
2. Golden, CA
3. Littleton, CA

The present invention provides an economical, simple, dry and controllable semiconductor layer junction forming process to make cadmium free high efficiency photovoltaic cells having a first layer comprised primarily of copper indium diselenide having a thin doped copper indium diselenide n-type region, generated by thermal diffusion with a group II(b) element such as zinc, and a halide, such as chlorine, and a second layer comprised of a conventional zinc oxide bilayer. A photovoltaic device according the present invention includes a first thin film layer of semiconductor material formed primarily from copper indium diselenide. Doping of the copper indium diselenide with zinc chloride is accomplished using either a zinc chloride solution or a solid zinc chloride material. Thermal diffusion of zinc chloride into the copper indium diselenide upper region creates the thin n-type copper indium diselenide surface. A second thin film layer of semiconductor material comprising zinc oxide is then applied in two layers. The first layer comprises a thin layer of high resistivity zinc oxide. The second relatively thick layer of zinc oxide is doped to exhibit low resistivity.

• Research Organization: Midwest Research Institute
• DOE Contract Number: AC36-83CH10093
• Assignee: Midwest Research Institute (Kansas City, MO)
• Patent Number(s): US 5948176
• OSTI ID: 872498
• Country of Publication: United States
• Language: English

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