Photovoltaic devices with an interfacial band-gap modifying structure and methods for forming the same

Patent metadata

Field	Value
Publication number	US-10283668-B2
Application number	US-201615229604-A
Country	US
Kind code	B2
Filing date	Aug 5, 2016
Priority date	Aug 4, 2010
Publication date	May 7, 2019
Grant date	May 7, 2019

Abstract

A Schottky-barrier-reducing layer is provided between a p-doped semiconductor layer and a transparent conductive material layer of a photovoltaic device. The Schottky-barrier-reducing layer can be a conductive material layer having a work function that is greater than the work function of the transparent conductive material layer. The conductive material layer can be a carbon-material layer such as a carbon nanotube layer or a graphene layer. Alternately, the conductive material layer can be another transparent conductive material layer having a greater work function than the transparent conductive material layer. The reduction of the Schottky barrier reduces the contact resistance across the transparent material layer and the p-doped semiconductor layer, thereby reducing the series resistance and increasing the efficiency of the photovoltaic device.

First claim

What is claimed is:

1. A method of forming a photovoltaic device comprising:
forming a transparent conductive material layer on a substrate;
forming a Schottky-barrier-reducing layer directly on said transparent conductive material layer, wherein said Schottky-barrier-reducing layer is an optically transparent layer consisting essentially of single wall carbon nanotubes; and
forming a p-doped semiconductor layer directly on said Schottky-barrier-reducing layer, wherein a Schottky barrier across a stack of said transparent conductive material layer, said Schottky-barrier-reducing layer, and said p-doped semiconductor layer has a lower contact resistance than a Schottky barrier across a comparative exemplary stack that includes all layers of said stack less said Schottky-barrier-reducing layer;
forming an intrinsic semiconductor layer directly on said p-doped semiconductor layer;
forming an n-doped semiconductor layer that contacts said intrinsic semiconductor layer; and
forming a back reflector layer that is in direct contact with said n-doped semiconductor layer.

2. The method of claim 1 , wherein said transparent conductive material layer comprises aluminum-doped zinc oxide.

3. The method of claim 1 , wherein said transparent conductive material layer comprises fluorine-doped tin oxide.

4. The method of claim 1 , wherein said Schottky-barrier-reducing layer has a higher resistivity than a material of said transparent conductive material layer.

5. The method of claim 1 , wherein said Schottky-barrier-reducing layer has a work function that is greater than a work function of said transparent conductive material layer and is lesser than an absolute value of a Fermi level energy of said p-doped semiconductor layer.

6. The method of claim 1 , wherein said intrinsic semiconductor layer includes a hydrogenated amorphous intrinsic semiconductor material.

7. The method of claim 1 , wherein said n-doped semiconductor layer includes hydrogenated n-doped amorphous semiconductor material.

8. The method of claim 1 , wherein the p-doped semiconductor layer comprises a p-doped silicon material.

9. The method of claim 1 , further comprising forming a metallic back reflector layer directly on said back reflector layer.

10. The method of claim 1 , wherein said back reflector layer is optically transparent and comprises n-type materials.

11. The method of claim 1 , wherein said n-doped semiconductor layer is formed directly on said intrinsic semiconductor layer.

12. The method of claim 11 , wherein the back reflector layer comprises a transparent conductive oxide.

Assignees

• IBM
• Egypt Nanotechnology Center

Inventors

• Fogel Keith E
• Kim Jeehwan
• Sadana Devendra K
• Tulevski George S
• Abou-Kandil Ahmed
• Mohamed Hisham S
• Saad Mohamed
• Tobail Osama

Classifications

• H01L31/056

  Electricity · mapped topic

• H01L31/02327

  Electricity · mapped topic

• H01L31/1884 Primary

  Electricity · mapped topic

• H01L31/028

  Electricity · mapped topic

• H01L31/075

  Electricity · mapped topic