Photovoltaic device, manufacturing method of photovoltaic device, photovoltaic device integrated with building material and power-generating apparatus

• US 6,222,117 B1
• Filed: 12/29/1998
• Issued: 04/24/2001
• Est. Priority Date: 01/05/1998
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shiozaki, Atsushi
• Primary Examiner(s): Robinson, Ellis
• Assistant Examiner(s): Miggins, Michael C.
• Application Number:
  US09/221,870
• Time in Patent Office: 847 Days
• Field of Search: 136/256, 136/258, 136/255
• US Class Current: 136/256
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/02366 of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/056 the light-reflecting means being of the back surface reflector [BSR] 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 31/182 Special manufacturing methods for polycrystalline Si, e.g. Si ribbon, poly Si ingots, thin films of polycrystalline Si
• CPC Class Codes: H01L 31/1824 Special manufacturing methods for microcrystalline Si, uc-Si
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/545 Microcrystalline silicon PV cells
• CPC Class Codes: Y02E 10/546 Polycrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

The present invention provides a photovoltaic device being capable of generating a large amount of current even with thin joined semiconductor layers, has a high photoelectric conversion efficiency and can be manufactured inexpensively at a low temperature together with a manufacturing method of the same, a photovoltaic device integrated with a building material and a power-generating apparatus. The photovoltaic device is formed by depositing joined semiconductor layers on a substrate, wherein a ratio of projected areas of regions on a surface of the joined semiconductor layers that have heights not smaller than a center value of concavities and convexities to a projected area of the entire surface of the joined semiconductor layers is higher than a ratio of projected areas of regions on the surface of the substrate that have heights not smaller than the center value of concavities and convexities on a surface of the substrate to a projected area of the entire surface of the substrate.

Claims

1. A photovoltaic device comprising joined semiconductor layers on a substrate,

wherein the substrate has a substantially planar surface with

(a) concavities and convexities,

(b) a highest point, and

(c) a lowest point, such that

(i) a substrate center value that is the mean elevation between said highest point and said lowest point can be determined,

(ii) a total, TA_sub-above, of projected areas of regions of the substrate surface that lie at or above the substrate center value can be determined, each said projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(iii) a total, TA_sub-entire, of the projected area of the entire substrate surface can be determined;

and the joined semiconductor layers have a substantially planar surface with

(d) concavities and convexities,

(e) a highest point, and

(f) a lowest point, such that

(iv) a semiconductor center value that is the mean elevation between said highest point and said lowest point can be determined,

(v) a total, TA_semi-above, of projected areas of regions of the surface of the joined semiconductor layers that lie at or above the semiconductor center value can be determined, each projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(vi) a total, TA_semi-entire, of the projected area of the entire surface of the joined semiconductor layers can be determined; and

wherein the ratio of TA_sub-above to TA_sub-entire is greater than the ratio of TA_sub-above to TA_sub-entire.

2. The photovoltaic device according to claim 1, wherein the ratio of TA_semi-above to TA_semi-entire is 10% or more greater than the ratio of TA_sub-above to TA_sub-entire.

3. The photovoltaic device according to claim 1, wherein the joined semiconductor layers comprise a first semiconductor layer selected from the group consisting of n type and p type semiconductor layers, a second semiconductor layer selected from the group consisting of weak n type, weak p type and i type semiconductor layers and a third semiconductor layer which is different from the first semiconductor layer and is selected from the group consisting of n type and p type semiconductor layers.

4. The photovoltaic device according to claim 3, wherein the i type semiconductor layer comprises a microcrystalline semiconductor.

5. The photovoltaic device according to claim 3, wherein a quotient of a short-circuit current under sunlight of A.M. 1.5 (100 mW/cm²) divided by a thickness of the second semiconductor layer is 20 mA/cm²/μ

m or higher.

6. The photovoltaic device according to claim 1, wherein the substrate comprises a first electrode layer, and wherein a second electrode layer is provided on the joined semiconductor layers.

7. The photovoltaic device according to claim 1, wherein a mean height of the surface of the substrate is 100 to 150 nm and a mean centerline roughness Ra of the surface of the substrate is 100 to 200 nm, and wherein the ratio of TA_sub-above to TA_sub-entire is 40 to 80%.

8. The photovoltaic device according to claim 1, wherein the surface of the substrate comprises at least one metal selected from the group consisting of stainless steel, silver, iron, nickel and aluminium.

9. The photovoltaic device according to claim 1, wherein a transparent conductive layer comprising at least one oxide selected from the group consisting of zinc oxide, tin oxide, indium oxide and titanium oxide is provided on the surface of the substrate.

10. The photovoltaic device according to claim 1, wherein at least a part of the joined semiconductor layers comprises silicone, hydrogen and a crystalline phase, the crystalline phase exhibiting a peak indicative of a (220) surface when analyzed by X-ray diffraction.

11. The photovoltaic device according to claim 1, wherein at least a part of the joined semiconductor layers comprises silicon, hydrogen and a crystalline phase, the crystalline phase exhibiting a peak at 510 to 530 cm⁻

1 when analyzed by Ramam spectroscopy using a laser beam of 514.5 nm.

12. The photovoltaic device according to claim 1, wherein there are provided two or more sets of the joined semiconductor layers, each set comprising a first semiconductor layer selected from the group consisting of n type and p type semiconductor layers, a second semiconductor layer selected from the group consisting of weak n type, weak p type and i type semiconductor layers and a third semiconductor layer which is different from the first semiconductor layer and is selected from the group consisting of n type and p type semiconductor layers.

13. The photovoltaic device according to claim 12, wherein a quotient of a short-circuit current under sunlight of A.M. 1.5 (100 mW/cm²) divided by a thickness of the second semiconductor layer is 20 mA/cm²/μ

m or higher.

14. The photovoltaic device according to claim 12, wherein at least one layer of the i type semiconductor layers comprises a microcrystalline semiconductor.

15. A photovoltaic device integrated with a building material comprising:

a photovoltaic device comprising joined semiconductor layers on a substrate;

a back surface reinforcing member; and

a sealing member which integrally seals the photovoltaic device and the back surface reinforcing member,

wherein the substrate has a substantially planar surface with

(a) concavities and convexities,

(b) a highest point, and

(c) a lowest point, such that

(i) a substrate center value that is the mean elevation between said highest point and said lowest point can be determined,

(ii) a total, TA_sub-above, of projected areas of regions of the substrate surface that lie at or above the substrate center value can be determined, each said projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(iii) a total, TA_sub-entire, of the projected area of the entire substrate surface can be determined;

and the joined semiconductor layers have a substantially planar surface with

(d) concavities and convexities,

(e) a highest point, and

(f) a lowest point, such that

(iv) a semiconductor center value that is the mean elevation between said highest point and said lowest point can be determined,

(v) a total, TA_semi-above, of projected areas of regions of the surface of the joined semiconductor layers that lie at or above the semiconductor center value can be determined, each projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(vi) a total, TA_semi-entire, of the projected area of the entire surface of the joined semiconductor layers can be determined; and

wherein the ratio of TA_semi-above to TA_semi-entire is greater than the ratio of TA_sub-above to TA_sub-entire.

16. A power-generating apparatus comprising:

a photovoltaic device comprising joined semiconductor layers on a substrate;

a power converter into which electric power from the photovoltaic device is input;

detecting means which detects an output voltage and output current from the photovoltaic device;

output setting means into which signals are input from the detecting means; and

a control circuit which controls the power converter on the basis of the signals input into the output setting means,

wherein the substrate has a substantially planar surface with

(a) concavities and convexities,

(b) a highest point, and

(c) a lowest point, such that

(i) a substrate center value that is the mean elevation between said highest point and said lowest point can be determined,

(ii) a total, TA_sub-above, of projected areas of regions of the substrate surface that lie at or above the substrate center value can be determined, each said projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(iii) a total, TA_sub-entire, of the projected area of the entire substrate surface can be determined;

and the joined semiconductor layers have a substantially planar surface with

(d) concavities and convexities,

(e) a highest point, and

(f) a lowest point, such that

(iv) a semiconductor center value that is the mean elevation between said highest point and said lowest point can be determined,

(v) a total, TA_semi-above, of projected areas of regions of the surface of the joined semiconductor layers that lie at or above the semiconductor center value can be determined, each projected area being the cross-sectional area of a columnar projection extending perpendicular from the region, and

(vi) a total, TA_semi-entire, of the projected area of the entire surface of the joined semiconductor layers can be determined; and

wherein the ratio of TA_semi-above to TA_semi-entire is greater than the ratio of TA_sub-above to TA_sub-entire.

17. The power-generating apparatus according to claim 16, wherein a plurality of the photovoltaic devices are connected in series or parallel.

18. The power-generating apparatus according to claim 16, wherein the power converter comprises a DC/DC converter using a self arc-suppression type switching element or a self excitation type DC/AC inverter.

19. The power-generating apparatus according to claim 16, wherein the output setting means determines an output setting value by performing calculations on the basis of detection signals from the detecting means to control an output voltage from the photovoltaic device to a predetermined value.

20. The power-generating apparatus according to claim 16, wherein the control circuit is a gate driving circuit which generates gate pulses by instantaneous current comparison or sinusoidal wave/triangular wave comparison.