High Power Efficiency Polycrystalline CdTe Thin Film Semiconductor Photovoltaic Cell Structures for Use in Solar Electricity Generation

• US 20110139249A1
• Filed: 12/10/2010
• Published: 06/16/2011
• Est. Priority Date: 12/10/2009
• Status: Abandoned Application

• Current Assignee: Uriel Solar, Inc.
• Original Assignee: Uriel Solar, Inc.
• Inventors: Wang, Shumin, Garnett, James David, Dingus, Peter
• Application Number:
  US12/965,800
• Publication Number:
  US 20110139249A1
• Time in Patent Office: Days
• US Class Current: 136/260
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/0248 Tellurides
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02562 Tellurides
• CPC Class Codes: H01L 21/02573 Conductivity type
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 31/03925 including AIIBVI compound materials, e.g. CdTe, CdS
• CPC Class Codes: H01L 31/065 the potential barriers being only of the graded gap type
• CPC Class Codes: H01L 31/073 comprising only AIIBVI compound semiconductors, e.g. CdS/CdTe solar cells
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• 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 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02E 10/543 Solar cells from Group II-VI materials
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

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);

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

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

a fourth layer comprising Zn and Te over the third layer; and

a superstrate below the first layer or over the fourth layer.

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

3. The photovoltaic device of claim 1, wherein the first layer is chemically doped n-type, the second layer is chemically doped n-type, the third layer is chemically doped p-type, and the fourth layer is chemically doped p-type.

4. The photovoltaic device of claim 1, wherein the superstrate is a substrate.

5. The photovoltaic device of claim 1, wherein the fourth layer further includes Cd.

6. A photovoltaic device, comprising:

a first n-type CdTe layer;

a second n-type CdTe layer over the first n-type CdTe layer;

a first p-type CdZnTe layer over the second n-type CdTe;

a second p-type ZnTe or CdZnTe layer over the first p-type CdZnTe layer; and

a superstrate adjacent or below the first n-type CdTe layer or adjacent or over the second p-type ZnTe or CdZnTe layer.

7. The photovoltaic device of claim 6, wherein the concentration of n-type chemical dopant in the first n-type CdTe layer is higher than the concentration of n-type chemical dopant in the second n-type CdTe layer.

8. The photovoltaic device of claim 6, wherein the concentration of p-type chemical dopant in the first p-type CdZnTe layer is lower than the concentration of p-type chemical dopant in the second p-type ZnTe or CdZnTe layer.

9. The photovoltaic device of claim 6, wherein the first p-type CdZnTe layer is compositionally graded in Cd and Zn.

10. The photovoltaic device of claim 6, wherein the second p-type ZnTe or CdZnTe layer comprises nitrogen (N) or arsenic (As).

11. The photovoltaic device of claim 6, wherein the first n-type CdTe layer comprises indium (In), iodine (I) or chlorine (Cl).

12. The photovoltaic device of claim 6, wherein the second n-type CdTe layer comprises indium (In), iodine (I) or chlorine (Cl).

13. The photovoltaic device of claim 6, wherein the first p-type CdZnTe layer comprises nitrogen (N) or arsenic (As).

14. The photovoltaic device of claim 6, wherein the superstrate is a substrate.

15. A photovoltaic device, comprising

an n-type layer including Te and Cd;

an intrinsic CdTe layer adjacent or over the n-type layer; and

a p-type layer including Te and Zn adjacent or over the intrinsic CdTe layer.

16. The photovoltaic device of claim 15, wherein the p-type layer further includes Cd

17. The photovoltaic device of claim 15, further comprising a superstrate adjacent or below the n-type layer

18. The photovoltaic device of claim 15, further comprising a superstrate adjacent or over the p-type layer.

19. The photovoltaic device of claim 15, further comprising a substrate adjacent or below the n-type layer or adjacent or over the p-type layer.

20. A method for forming a photovoltaic device, comprising:

forming a p+ ZnTe layer;

forming an intrinsic CdTe (i-CdTe) layer;

annealing the i-CdTe layer under an overpressure of Te, or Cd, or Cd and Zn, or Cd and Cl; and

forming an n+ CdTe layer.

21. A method for forming a photovoltaic device, comprising:

forming a p+ ZnTe layer;

forming a p-type CdZnTe layer and annealing under an overpressure of one or more of Cd, Zn, N or As;

forming an n-type CdTe layer and annealing under an overpressure of one or more of Cd, Zn, In, Cl, or I; and

forming an n+ CdTe layer.

22. The method of claim 21, wherein forming the p-type CdZnTe layer includes grading the CdZnTe layer in Cd and Zn.