Photovoltaic device

• US 7,301,215 B2
• Filed: 08/14/2006
• Issued: 11/27/2007
• Est. Priority Date: 08/22/2005
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kariya, Toshimitsu
• Primary Examiner(s): Purvis; Sue A.
• Assistant Examiner(s): TRAN, TAN N
• Application Number:
  US11/464,263
• Publication Number:
  US 20070040233A1
• Time in Patent Office: 470 Days
• Field of Search: 257/458, 257/E31.001, 257/E25.009, 136/256
• US Class Current: 257/458
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/022475 composed of indium tin oxide [ITO]
• CPC Class Codes: H01L 31/022483 composed of zinc oxide [ZnO]
• 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 31/03685 including microcrystalline silicon, uc-Si
• CPC Class Codes: H01L 31/03762 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: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/545 Microcrystalline silicon PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells

Abstract

A photovoltaic device includes at least a first electrode, a first-conductivity-type layer composed of non-single-crystalline silicon, a second-conductivity-type layer composed of polycrystalline silicon, a third-conductivity-type layer composed of non-single-crystalline silicon, and a second electrode, wherein the contact surface of the first electrode with respect to the first-conductivity-type layer has a shape interspersed with a plurality of projections, and the lower limit and the upper limit of the density of the projections interspersed on the surface of the first electrode satisfy the following equations, provided that the thickness of the second-conductivity-type layer is t μm:
Lower limit=0.312 exp(−0.60t) pieces/μm²
Upper limit=0.387 exp(−0.39t) pieces/μm².

Claims

1. A photovoltaic device comprising:

a first electrode;

a first-conductivity-type layer composed of non-single-crystalline silicon;

a second-conductivity-type layer composed of polycrystalline silicon;

a third-conductivity-type layer composed of non-single-crystalline silicon; and

a second electrode,

wherein a contact surface of the first electrode with respect to the first-conductivity-type layer has a shape interspersed with a plurality of projections, and the lower limit and the upper limit of the density of the projections interspersed on the surface of the first electrode satisfy the following equations, provided that the thickness of the second-conductivity-type layer is t μ

m;

Lower limit=0.312 exp(−

0.60t) pieces/μ

m²

Upper limit=0.387 exp(−

0.39t) pieces/μ

m².

2. The photovoltaic device according to claim 1, wherein a contact surface of the third-conductivity-type layer with respect to the second electrode has a plurality of curved convex portions.

3. The photovoltaic device according to claim 1 or 2, wherein the first electrode includes a reflection layer, a first transparent conductive layer, and a second transparent conductive layer, the second transparent conductive layer being in contact with the first-conductivity-type layer, the projections being present on the surface of the second transparent conductive layer.

4. The photovoltaic device according to claim 1 or 2, wherein the third-conductivity-type layer includes a plurality of sublayers, and among the plurality of sublayers, a sublayer in contact with the second-conductivity-type layer is a buffer layer composed of hydrogenated amorphous silicon.

5. The photovoltaic device according to claim 1 or 2, wherein the first electrode includes a layer composed of zinc oxide formed by electrodeposition.