Textured multi-junction solar cell and fabrication method
AssigneeInternational Business Machines Corporation
InventorsBahman Hekmatshoartabari, Ali Khakifirooz, Ghavam G. Shahidi, Davood Shahrjerdi
Life of this patent
Estimating the term…
Abstract
A method for forming a multi junction photovoltaic device includes providing a germanium layer and etching pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface. A first p-n junction is formed on or over the textured surface from III-V semiconductor materials. Another p-n junction is formed over the first p-n junction from III-V semiconductor materials and follows the textured surface.
Claims24
A method for forming a multi-junction photovoltaic device, comprising:
- providing a germanium layer;
- wet etching pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface, wherein the wet etching is performed using an acidic etchant including phosphoric acid, hydrogen peroxide and ethanol in a 1:1:1 ratio;
- forming a first p-n junction directly on the textured surface from III-V semiconductor materials, which follow the textured surface;
- and
- forming at least one other p-n junction directly on the first p-n junction from III-V semiconductor materials and following the textured surface.
A method for forming a multi junction photovoltaic device, comprising:
- providing a germanium layer;
- wet etching the germanium layer using an acidic etchant including phosphoric acid, hydrogen peroxide and ethanol in a 1:1:1 ratio;
- forming pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface;
- doping a top surface of the germanium layer to form a first p-n junction on or over the textured surface;
- depositing a first semiconductor layer on the top surface which follows a profile of the textured surface;
- and
- doping a portion of the first semiconductor layer to form a second p-n junction, wherein the second p-n junction is formed directly on the first p-n junction.
A method for forming a multi-junction photovoltaic device, comprising:
- providing one of bulk germanium or a germanium layer formed on a silicon substrate;
- wet etching the germanium layer using an acidic etchant including phosphoric acid, hydrogen peroxide and ethanol in a 1:1:1 ratio;
- forming pyramidal shapes in the germanium layer such that (111) facets are exposed to form a textured surface;
- doping a top surface of the germanium layer to form a first p-n junction on or over the textured surface;
- depositing a first semiconductor layer on the top surface which follows a profile of the textured surface, wherein the first semiconductor layer includes a GaAs layer or alloys thereof;
- doping a portion of the first semiconductor layer to form a second p-n junction;
- depositing a second semiconductor layer on the first semiconductor layer, the second semiconductor layer following the profile of the textured surface, wherein the second semiconductor layer includes a GaP layer or alloys thereof;
- and
- doping a portion of the second semiconductor layer to form a third p-n junction.
Dependencies are inferred from the claim text.