Patent ID: 11876140
Assignee: FIRST SOLAR, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  C  Y | IPC C  H

Claim 15:
16. A photovoltaic device, comprising:
a transparent layer stack; and
an absorber layer in direct contact with the transparent layer stack at a front interface of the absorber layer, wherein:
the absorber layer consists of a thickness of the absorber layer between the front interface of the absorber layer and a back interface of the absorber layer,
the front interface of the absorber layer is closer to the transparent layer stack than the back interface of the absorber layer,
the absorber layer comprises cadmium, selenium, and tellurium,
an atomic concentration of selenium varies across the thickness of the absorber layer,
the atomic concentration of selenium is greater at the front interface of the absorber layer relative to the back interface of the absorber layer,
the absorber layer is a p-type layer,
the absorber layer consists of a first region and a second region,
the first region extends from the front interface of the absorber layer to the second region,
the second region extends from the first region to the back interface of the absorber layer,
the first region has a continuous uniform thickness between 100 nanometers to 3000 nanometers thick,
the second region has a continuous uniform thickness between 100 nanometers to 3000 nanometers thick,
a ratio of an average atomic concentration of selenium in the first region to an average atomic concentration of selenium in the second region is greater than 10, and
the photovoltaic device has no window layer and is completely free of a cadmium sulfide layer.