Diode structure, especially for thin-filn solar cells

• US 20020043279A1
• Filed: 07/25/2001
• Published: 04/18/2002
• Est. Priority Date: 11/25/1999
• Status: Active Grant

• Current Assignee: Shell Erneuerbare Energien GmbH (Shell Plc)
• Original Assignee: Shell Solar GmbH
• Inventors: Karg, Franz
• Granted Patent: US 6,486,391 B2
• Time in Patent Office: Days
• US Class Current: 136/262
• CPC Class Codes: H01L 31/0322 comprising only AIBIIICVI chalcopyrite compounds, e.g. Cu In Se2, Cu Ga Se2, Cu In Ga Se2
• CPC Class Codes: H01L 31/0749 including a AIBIIICVI compound, e.g. CdS/CulnSe2 [CIS] heterojunction solar cells
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells

Abstract

The invention relates to a diode structure, especially for thin film solar cells. The aim of the invention is to provide a diode structure for thin film solar cells. Said structure allows for an assembly of a thin film solar cell, whereby said assembly is as flexible as possible, efficiency is high, and utilizing materials that are as environmentally friendly as possible. A diode structure comprising a p-conducting layer, which consists of a chalcopyrite compound, and a n-conducting layer, which is adjacent to the p-conducting layer and consists of a compound that contains titanium and oxygen, is provided.

Claims

1. A diode structure for thin-film solar cells, comprising:

a p-conducting layer comprising a chalcopyrite compound;

a n-conducting layer having a first band gap and comprising a compound, the compound containing titanium and oxygen, the n-conducting layer adjoining the p-conducting layer;

a n-conducting amplifying layer having a second band gap; and

wherein a side of the n-conducting layer facing away from the p-conducting layer adjoins the n-conducting amplifying layer; and

wherein the second band gap is larger than the first band gap.

2. The diode structure as claimed in claim 1, wherein the chalcopyrite compound is a I-III-VI₂ semiconductor from the group Cu(InGa)(SSe)₂.

3. The diode structure as claimed in claim 2, wherein the chalcopyrite compound comprises CuInSe₂ (CIS).

4. The diode structure as claimed in claim 1, wherein the compound containing titanium and oxygen is selected from a group TiO_x where x is in the range from greater than 1.5 to less than 2.0.

5. The diode structure as claimed in claim 4, wherein the compound containing titanium and oxygen is selected based on the chalcopyrite compound, so as to achieve a best possible adaptation in a conduction band.

6. The diode structure as claimed in claim 1, wherein the n-conducting amplifying layer comprises an oxide that is transparent and conductive.

7. The diode structure as claimed in claim 6, wherein the oxide is a doped metal oxide.

8. The diode structure as claimed in claim 7, wherein the oxide comprises any one of ZnO, SnO₂ and InSnO₂.

9. A thin-film solar cell comprising:

a diode structure, the diode structure comprising;

a p-conducting layer comprising a chalcopyrite compound;

a n-conducting layer having a first band gap and comprising a compound, the compound containing titanium and oxygen, the n-conducting layer adjoining the p-conducting layer;

a n-conducting amplifying layer having a second band gap; and

wherein a side of the n-conducting layer facing away from the p-conducting layer adjoins the n-conducting amplifying layer; and

wherein the second band gap is larger than the first band gap.

10. The thin-film solar cell as claimed in claim 9, wherein a layer thickness of the n-conducting layer is selected based on a surface resistivity of the n-conducting layer.

11. The thin-film solar cell as claimed in claim 9, wherein a side of the p-conducting layer facing away from the n-conducting layer adjoins a bus contact.

12. The thin-film solar cell as claimed in claim 11, wherein the n-conducting amplifying layer adjoins a substrate, the n-conducting amplifying layer facing away from a light incident side of the substrate.

13. The thin-film solar cell as claimed in claim 11, wherein the bus contact comprises molybdenum.

14. The thin-film solar cell as claimed in claim 11, wherein the bus contact is configured as a full surface area back electrode.

15. The thin-film solar cell as claimed in claim 11, wherein the bus contact adjoins a light incident side of a substrate.

16. The thin-film solar cell as claimed in claim 15, wherein the substrate comprises glass.