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

Patent metadata

Field	Value
Publication number	US-10297709-B2
Application number	US-201615156940-A
Country	US
Kind code	B2
Filing date	May 17, 2016
Priority date	Aug 4, 2010
Publication date	May 21, 2019
Grant date	May 21, 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 photovoltaic device comprising a stack, from one side to another side, of:
a transparent conductive material layer;
a Schottky-barrier-reducing layer contacting said transparent conductive material layer, wherein said Schottky-barrier-reducing layer is an optically transparent layer consisting essentially of single wall carbon nanotubes; and
a p-doped semiconductor layer, wherein a Schottky barrier across said stack 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, and wherein said Schottky-barrier-reducing layer is in direct contact with said p-doped semiconductor layer;
an intrinsic semiconductor layer contacting said p-doped semiconductor layer;
an n-doped semiconductor layer directly on said intrinsic semiconductor layer; and
a back reflector layer in direct contact with said n-doped semiconductor layer.

2. The photovoltaic device of claim 1 , wherein the p-doped semiconductor layer comprises a p-doped silicon material.

3. The photovoltaic device of claim 1 , wherein said intrinsic semiconductor layer includes a hydrogenated amorphous intrinsic semiconductor material.

4. The photovoltaic device of claim 1 , wherein said n-doped semiconductor layer includes hydrogenated n-doped amorphous semiconductor material.

5. The photovoltaic device of claim 1 , further comprising a metallic back reflector layer located on said back reflector layer.

6. The photovoltaic device of claim 1 , wherein said Schottly-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 of said p-doped semiconductor layer.

7. The photovoltaic device of claim 1 , wherein a series resistance of said photovoltaic device is equal to or less than 9 Ohms-cm 2 .

8. The photovoltaic device of claim 1 , wherein said p-doped semiconductor layer includes a hydrogenated p-doped semiconductor-containing material.

9. The photovoltaic device of claim 1 , wherein said transparent conductive material layer comprises aluminum-doped zinc oxide having an aluminum doping at a first dopant concentration.

10. The photovoltaic device of claim 1 , wherein said transparent conductive material layer comprises fluorine-doped tin oxide having an fluorine doping at a first dopant concentration.

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

12. The photovoltaic device of claim 1 , wherein said back reflector layer comprises an optically transparent conductive oxide selected from the group consisting of a fluorine-doped tin oxide, an aluminum-doped zinc oxide and an indium tin oxide.

13. The photovoltaic device of claim 1 , wherein a series resistance of said photovoltaic device is 2 Ohms-cm 2 .

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

• Y02E10/548

  Amorphous silicon PV cells · CPC title

• Y02E10/52

  PV systems with concentrators · CPC title

• H01L2031/0344

  Electricity · mapped topic

• H01L31/075

  Electricity · mapped topic

• H01L31/022483

  Electricity · mapped topic