SOLAR CELL

• US 20120080082A1
• Filed: 03/10/2011
• Published: 04/05/2012
• Est. Priority Date: 10/04/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: SUH, Myoung Gyun
• Granted Patent: US 8,507,787 B2
• Time in Patent Office: Days
• US Class Current: 136/255
• CPC Class Codes: H01L 31/03042 characterised by the doping material
• CPC Class Codes: H01L 31/0735 comprising only AIIIBV compound semiconductors, e.g. GaAs/AlGaAs or InP/GaInAs solar cells
• CPC Class Codes: H01L 31/184 the active layers comprising only AIIIBV compounds, e.g. GaAs, InP
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials

Abstract

A solar cell includes a base layer; an emitter layer disposed on one side of the base layer; a first electrode in electrical communication with the base layer; and a second electrode in electrical communication with the emitter layer, wherein the base layer has a higher doping concentration with increasing distance from the interface between the base layer and the emitter layer, and the base layer has a doping concentration change slope that is further decreased with increasing distance from the interface between the base layer and the emitter layer.

Claims

1. A solar cell comprising:

a base layer;

an emitter layer disposed on one side of the base layer;

a first electrode in electrical communication with the base layer; and

a second electrode in electrical communication with the emitter layer,

wherein the base layer has a higher doping concentration with increasing distance from an interface between the base layer and the emitter layer, and

the base layer has a doping concentration change slope that is decreased with increasing distance from the interface between the base layer and the emitter layer.

2. The solar cell of claim 1, wherein the base layer has a thickness of about 100 nanometers to about 200 micrometers.

3. The solar cell of claim 1, wherein the base layer has a constant doping concentration up to ⅖

of the entire base layer thickness from the interface between the base layer and the emitter layer.

4. The solar cell of claim 1, wherein the doping concentration of the base layer is continuously changed.

5. The solar cell of claim 1, wherein the doping concentration of base layer is discontinuously changed.

6. The solar cell of claim 5, wherein the base layer has a distinguishable plurality of doping levels, and a thickness having the constant doping concentration of each doping level is smaller than a diffusion length of a minority carrier.

7. The solar cell of claim 5, wherein the base layer has a distinguishable plurality of doping levels, and a doping thickness in each doping level becomes thinner with increasing distance from the interface between the base layer and the emitter layer.

8. The solar cell of claim 1, wherein the base layer has a doping concentration of about 1×

10¹⁵ cm<sup>−

3</sup> to about 1×

10¹⁹ cm<sup>−

3</sup>.

9. The solar cell of claim 1, wherein the emitter layer has a thickness of about 10 nanometer to about 1 micrometer.

10. The solar cell of claim 1, wherein the emitter layer has a doping concentration of about 1×

10¹⁷ cm<sup>−

3</sup> to about 1×

10²⁰ cm<sup>−

3</sup>.

11. The solar cell of claim 1, further comprising an auxiliary layer disposed between the base layer and the emitter layer.

12. The solar cell of claim 11, wherein the auxiliary layer has a smaller doping concentration than a doping concentration of the base layer and a doping concentration of the emitter layer.

13. The solar cell of claim 11, wherein the auxiliary layer has a doping concentration of about 1×

10¹⁰ cm<sup>−

3</sup> to about 1×

10¹⁶ cm<sup>−

3</sup>.

14. The solar cell of claim 11, wherein the auxiliary layer has a thickness of about 10 nanometer to about 200 nanometer.

15. The solar cell of claim 1, wherein the solar cell is a multijunction solar cell.

16. The solar cell of claim 1, further comprising a window layer and a contact layer sequentially disposed on a surface of the emitter layer.

17. A method comprising:

disposing an emitter layer on one side of a base layer;

electrically contacting a first electrode with the base layer; and

electrically contacting a second electrode with the emitter layer,

wherein the base layer has a higher doping concentration with increasing distance from an interface between the base layer and the emitter layer, and the base layer has a doping concentration change slope that is decreased with increasing distance from the interface between the base layer and the emitter layer.

18. The method of claim 17, further comprising disposing an auxiliary layer between the base layer and the emitter layer.

19. The method of claim 17, wherein the first electrode and/or the second electrode is formed by screen printing, inkjet printing, press printing or a combination comprising at least one of the foregoing methods of printing.