High power efficiency, large substrate, polycrystalline CdTe thin film semiconductor photovoltaic cell structures grown by molecular beam epitaxy at high deposition rate for use in solar electricity generation

• US 8,664,524 B2
• Filed: 07/17/2009
• Issued: 03/04/2014
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Uriel Solar, Inc.
• Original Assignee: Uriel Solar, Inc.
• Inventors: Garnett, James David
• Primary Examiner(s): Pillay, Devina
• Application Number:
  US12/505,369
• Publication Number:
  US 20100012188A1
• Time in Patent Office: 1,691 Days
• Field of Search: 136/260, 136/255, 136/264, 136/265, 438/84, 438/97
• US Class Current: 136/260
• CPC Class Codes: H01L 31/0296 including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe
• CPC Class Codes: H01L 31/02966 including ternary compounds, e.g. HgCdTe
• CPC Class Codes: H01L 31/0392 including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate textured substrates H01L31/02366
• CPC Class Codes: H01L 31/03925 including AIIBVI compound materials, e.g. CdTe, CdS
• CPC Class Codes: H01L 31/0725 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/073 comprising only AIIBVI compound semiconductors, e.g. CdS/CdTe solar cells
• CPC Class Codes: H01L 31/078 including different types of potential barriers provided for in two or more of groups H01L31/062 - H01L31/075
• CPC Class Codes: H01L 31/1828 the active layers comprising only AIIBVI compounds, e.g. CdS, ZnS, CdTe
• CPC Class Codes: H01L 31/1832 comprising ternary compounds, e.g. Hg Cd Te
• CPC Class Codes: H01L 31/1836 comprising a growth substrate not being an AIIBVI compound
• CPC Class Codes: Y02E 10/543 Solar cells from Group II-VI materials
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Solar cell structures formed using molecular beam epitaxy (MBE) that can achieve improved power efficiencies in relation to prior art thin film solar cell structures are provided. A reverse p-n junction solar cell device and methods for forming the reverse p-n junction solar cell device using MBE are described. A variety of n-p junction and reverse p-n junction solar cell devices and related methods of manufacturing are provided. N-intrinsic-p junction and reverse p-intrinsic-n junction solar cell devices are also described.

Claims

1. A photovoltaic device, comprising:

a first layer comprising tellurium (Te) and cadmium (Cd) or zinc (Zn) over a substrate;

a second layer comprising Cd, Te and Zn over the first layer; and

a third layer comprising Cd, Te and Zn over the second layer, wherein the first layer is chemically doped p-type, the second layer is chemically doped p-type, and the third layer is chemically doped n-type.

2. The photovoltaic device of claim 1, wherein the second layer is compositionally graded in Cd and Zn.

3. The photovoltaic device of claim 1, wherein the third layer is compositionally graded in Cd and Zn.

4. The photovoltaic device of claim 1, further comprising a fourth layer comprising Cd, Zn and Te over said third layer, wherein said fourth layer is doped n-type.

5. A photovoltaic device, comprising:

a first p-type layer comprising Zn and Te over a substrate;

a second p-type layer comprising Cd, Te and Zn over the first p-type layer;

a first n-type layer comprising Cd, Zn and Te over the second p-type layer; and

a second n-type layer comprising Cd, Zn and Te over the first n-type layer.

6. The photovoltaic device of claim 5, wherein the concentration of an n-type chemical dopant in the first n-type layer is lower than the concentration of an n-type chemical dopant in the second n-type layer.

7. The photovoltaic device of claim 5, wherein the first n-type layer is compositionally graded in Cd and Zn.

8. The photovoltaic device of claim 5, wherein the first n-type layer comprises indium (In).

9. The photovoltaic device of claim 5, wherein the second n-type layer comprises indium (In).

10. The photovoltaic device of claim 5, wherein the substrate is a superstrate.