Machine and process for continuous, sequential, deposition of semiconductor solar absorbers having variable semiconductor composition deposited in multiple sublayers

摘要

A method of manufacture of I-III-VI-absorber photovoltaic cells involves sequential deposition of films comprising one or more of silver and copper, with one or more of aluminum indium and gallium, and one or more of sulfur, selenium, and tellurium, as compounds in multiple thin sublayers to form a composite absorber layer. In an embodiment, the method is adapted to roll-to-roll processing of photovoltaic cells. In an embodiment, the method is adapted to preparation of a CIGS absorber layer having graded composition through the layer of substitutions such as tellurium near the base contact and silver near the heterojunction partner layer, or through gradations in indium and gallium content. In a particular embodiment, the graded composition is enriched in gallium at a base of the layer, and silver at the top of the layer. In an embodiment, each sublayer is deposited by co-evaporation of copper, indium, gallium, and selenium, which react in-situ to form CIGS.

主权项

1. A method for forming a thin-film photovoltaic cell, comprising:
depositing from vapor (a) Copper, (b) Indium, (c) Aluminum or Gallium, and (d) Tellurium on a back contact layer of a substrate to form a first semiconductor material; reacting the first semiconductor material to form a first semiconductor solar absorber sublayer on the back contact layer; after the step of reacting the first semiconductor material, depositing from vapor, on the first semiconductor solar absorber sublayer, at least (a) Copper or Silver, (b) Indium, (c) Aluminum or Gallium, and (d) Selenium to form a second semiconductor material; reacting the second semiconductor material to form a second semiconductor solar absorber sublayer; after the step of reacting the second semiconductor material, depositing from vapor, on the second semiconductor solar absorber sublayer, (a) Silver, (b) Indium, (c) Aluminum or Gallium, and (d) Selenium to form a final semiconductor material; reacting the final semiconductor material to form a final semiconductor solar absorber sublayer; forming a heterojunction partner layer on the final semiconductor solar absorber sublayer; and forming a top contact layer on the heterojunction partner layer, the first semiconductor material having a greater concentration of Tellurium than the final semiconductor material, and the final semiconductor material having a greater concentration of Silver than the first semiconductor material.