FIELD-EFFECT PHOTOVOLTAIC ELEMENTS

• US 20130180564A1
• Filed: 01/13/2012
• Published: 07/18/2013
• Est. Priority Date: 01/13/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hekmatshoartabari, Bahman, Sadana, Devendra K., Haensch, Wilfried E., Shahidi, Ghavam G., Shahrjerdi, Davood
• Granted Patent: US 10,199,524 B2
• Time in Patent Office: Days
• US Class Current: 136/244
• CPC Class Codes: H01L 31/022433 Particular geometry of the grid contacts
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/0304 including, apart from doping materials or other impurities, only AIIIBV compounds
• CPC Class Codes: H01L 31/062 the potential barriers being only of the metal-insulator-semiconductor type
• 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 31/076 Multiple junction or tandem solar cells
• CPC Class Codes: H01L 31/1126 the device being a field-effect phototransistor
• CPC Class Codes: H01L 31/1133 the device being a conductor-insulator-semiconductor diode or a CCD device
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

Abstract

Photovoltaic devices such as solar cells having one or more field-effect hole or electron inversion/accumulation layers as contact regions are configured such that the electric field required for charge inversion and/or accumulation is provided by the output voltage of the photovoltaic device or that of an integrated solar cell unit. In some embodiments, a power source may be connected between a gate electrode and a contact region on the opposite side of photovoltaic device. In other embodiments, the photovoltaic device or integrated unit is self-powering.

Claims

1. A photovoltaic structure comprising:

an absorption layer having first and second sides;

a dielectric layer in direct contact with the first side of the absorption layer;

at least one first contact region in direct contact with the dielectric layer and the absorption layer;

a first electrode in direct contact with the dielectric layer, the first electrode being highly electrically conductive;

a second contact region in direct contact with the second side of the absorption layer, one of the first and second contact regions being low work-function with respect to the absorption layer and the other of the first and second contact regions being high work-function with respect to the absorption layer, the first electrode being electrically connected to the second contact region, and

a second electrode on the second side of the absorption layer and in direct contact with the second contact region, the second electrode being highly electrically conductive.

2. The photovoltaic structure of claim 1, further including a power supply connected in series between the first electrode and the second contact region.

3. The photovoltaic structure of claim 1, wherein the first electrode is directly connected to the second contact region.

4. The photovoltaic structure of claim 1, farther including an additional first contact region in direct contact with the dielectric layer and the absorption layer, the first contact regions having the same work-function with respect to the absorption layer.

5. A photovoltaic structure comprising:

an absorption layer having first and second sides;

a first dielectric layer in direct contact with the first side of the absorption layer;

a second dielectric layer in direct contact with the second side of the absorption layer;

a first contact region in direct contact with the first dielectric layer and the absorption layer;

a first electrode in direct contact with the first dielectric layer, the first electrode being highly electrically conductive;

a second contact region in direct contact with the second dielectric layer and the absorption layer, one of the first and second contact regions being low work-function with respect to the absorption layer and the other of the first and second contact regions being high work-function with respect to the absorption layer, the first electrode being electrically connected to the second contact region,

a second electrode on the second side of the absorption layer and in direct contact with the second dielectric region, the second electrode being highly electrically conductive and electrically connected to the first contact region.

6. The photovoltaic structure of claim 5, further including a power supply connected in series between the first electrode and the second contact region.

7. The photovoltaic structure of claim 5, wherein the first electrode is directly connected to the second contact region.

8. The photovoltaic structure of claim 5, further including an additional first contact region in direct contact with the first dielectric layer and the absorption layer and an additional second contact region in direct contact with the second dielectric layer and the absorption layer, the first contact regions having the same work-function with respect to the absorption layer, the second contact regions having the same work-function with respect to the absorption layer and opposite to the work-function of the first contact regions.

9. A photovoltaic structure comprising:

an absorption layer;

a dielectric layer in direct contact with the absorption layer;

one or more high work-function contact regions in direct contact with the absorption layer;

one or more low work-function contact regions in direct contact with the absorption layer;

a gate electrode in direct contact with the dielectric layer and electrically connected to one of the contact regions;

a first terminal connected to one of the one or more high work-function contact regions;

a second terminal connected to one of the one or more low work-function contact regions, and

a gate terminal connected to the gate electrode.

10. The photovoltaic structure of claim 9, wherein the one or more low work-function contact regions and the one or more high work-function contact regions are located on a first side of the absorption layer and the dielectric layer is located on a second side of the absorption layer.

11. The photovoltaic structure of claim 10, wherein the absorption layer is an intrinsic hydrogenated amorphous, nano-crystalline or microcrystalline semiconductor layer, the contact regions and absorption layer being configured as a p-i-n or n-i-p solar cell.

12. The photovoltaic structure of claim 11, wherein the dielectric layer comprises a-SiN_x:

H, a-SiO_x;

H, or combinations thereof.

13. The photovoltaic structure of claim 12, wherein the gate electrode is comprised of a transparent conductive oxide.

14. The photovoltaic structure of claim 10, wherein the absorption layer contains Si, Ge, C or combinations thereof.

15. The photovoltaic structure of claim 10, wherein the absorption layer is an intrinsic hydrogenated amorphous silicon semiconductor.

16. The photovoltaic structure of claim 9, wherein the gate electrode is comprised of a transparent conductive oxide.

17. The photovoltaic structure of claim 10, wherein the absorption layer comprises n-type or p-type gallium arsenide.

18. The photovoltaic structure of claim 17, wherein at least one of the contact regions is a Schottky source/drain device.

19. The photovoltaic structure of claim 17, wherein at least one of the contact regions is a back surface field layer.

20. The photovoltaic structure of claim 17, further including a transparent insulating substrate, the gate electrode being bonded to the transparent insulating substrate.

21. The photovoltaic structure of claim 10, further including a power supply connected between the gate electrode and one of the contact regions.

22. A photovoltaic circuit comprising:

a plurality of solar cell devices, each solar cell device comprising;

an absorption layer;

a dielectric layer in direct contact with the absorption layer;

one or more high work-function contact regions in direct contact with the absorption layer;

one or more low work-function contact regions in direct contact with the absorption layer,

a gate electrode in direct contact with the dielectric layer and electrically connected to one of the contact regions;

a first terminal connected to one of the one or more high work-function contact regions;

a second terminal connected to one of the one or more low work-function contact regions, and

a gate terminal connected to the gate electrode,

the solar cell devices being electrically connected in series and wherein the gate terminal of at least one of the solar cell devices is electrically connected to one of the first and second terminals of another of the solar cell devices.

23. The photovoltaic circuit of claim 22, further comprising a power supply electrically connected between the gate terminal of at least one of the solar cell devices and one of the first and second terminals of another of the solar cell devices.

24. The photovoltaic circuit of claim 22, wherein the absorption layer of one or more of the solar cell devices comprises an intrinsic amorphous hydrogenated silicon semiconductor layer.

25. The photovoltaic circuit of claim 22, wherein the absorption layer of one or more of the solar cell devices comprises n or p type gallium arsenide.