HETEROJUNCTION SOLAR CELL WITH ABSORBER HAVING AN INTEGRATED DOPING PROFILE

• US 20110174374A1
• Filed: 06/30/2009
• Published: 07/21/2011
• Est. Priority Date: 07/01/2008
• Status: Abandoned Application

• Current Assignee: Institut Fur Solarenergieforschung GmbH (State of Lower Saxony)
• Original Assignee: Institut Fur Solarenergieforschung GmbH (State of Lower Saxony)
• Inventors: Harder, Nils-Peter
• Application Number:
  US13/002,089
• Publication Number:
  US 20110174374A1
• Time in Patent Office: Days
• US Class Current: 136/258
• CPC Class Codes: H01L 31/028 including, apart from doping material or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/03762 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/0745 comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
• CPC Class Codes: H01L 31/0747 comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

Abstract

The invention relates to a heterojunction solar cell and a method for the production thereof. The heterojunction solar cell has an absorber layer made of silicon with a basic doping and at least one heterojunction layer of a doped semiconductor material whose band gap differs from that of the silicon of the absorber layer. The absorber layer has a doped layer at an interface directed toward the heterojunction layer, the doping concentration of said doped layer being greater than the basic doping concentration of the absorber layer. As a result of this doping profile, a field effect can be caused which prevents charge carrier pairs produced within the absorber layer from diffusing toward the interface between the absorber layer and the heterojunction layer and from recombining there.

Claims

1. Heterojunction solar cell, comprising:

an absorber layer of silicon with a base doping concentration;

a heterojunction layer of a doped semiconductor material, the band gap of which differs from that of the silicon of the absorber layer;

wherein the absorber layer has, at an interface directed towards the heterojunction layer, a doped layer, the doping concentration of which is higher than the base doping concentration of the absorber layer.

2. Solar cell according to claim 1,

wherein the absorber layer comprises crystalline silicon.

3. Solar cell according to claim 1,

wherein the heterojunction layer comprises amorphous silicon.

4. Solar cell according to claim 1,

wherein the doped layer within the absorber layer has a maximum doping agent concentration of between 1×

10¹⁷ cm<sup>−

3</sup> and 1×

10²⁰ cm<sup>−

3</sup>.

5. Solar cell according to claim 1,

wherein the doped layer has a doping profile with a doping agent concentration decreasing in a direction directed away from the interface.

6. Solar cell according to claim 1,

wherein the doped layer has a doping profile resulting from diffusion processes.

7. Solar cell according to claim 1,

wherein the doped layer has a depth of less than 2 μ

m.

8. Solar cell according to claim 1,

wherein the heterojunction layer directly abuts to the absorber layer.

9. Solar cell according to claim 1,

wherein an intrinsic layer is inserted between the heterojunction layer and the absorber layer.

10. Solar cell according to claim 1,

wherein the heterojunction layer and the doped layer of the absorber layer comprise the same semiconductor type.

11. Method for the production of a heterojunction solar cell,

wherein the method comprises:

providing an absorber layer of silicon essentially homogeneously doped with a base doping;

introducing of doping agents into the absorber layer to produce a doped layer, the doping concentration of which is higher than the base doping concentration of the absorber layer;

depositing of a heterojunction layer of a doped semiconductor material, the band gap of which differs from that of the silicon of the absorber layer, on to the surface of the absorber layer.

12. Method according to claim 11,

wherein the doped layer is produced with a doping profile with a doping agent concentration decreasing in a direction directed away from a surface of the absorber layer.

13. Method according to claim 11,

wherein the doping agents are introduced by diffusion.