Photovoltaic device

• US 8,049,101 B2
• Filed: 09/29/2005
• Issued: 11/01/2011
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Terakawa, Akira
• Primary Examiner(s): Hendricks; Keith
• Assistant Examiner(s): DINH, BACH T
• Application Number:
  US11/237,788
• Publication Number:
  US 20060065297A1
• Time in Patent Office: 2,224 Days
• Field of Search: 136243-265
• US Class Current: 136/258
• CPC Class Codes: H01L 31/0747 comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

In the photovoltaic devices comprising a substantially intrinsic amorphous silicon layer containing hydrogen between an n-type single-crystal silicon substrate and a p-type amorphous silicon layer containing hydrogen, the photovoltaic device according to the present invention comprises a trap layer that contains less hydrogen than the intrinsic amorphous silicon layer between the p-type amorphous silicon layer and the intrinsic amorphous silicon layer. The trap layer reduces hydrogen diffusion from the intrinsic amorphous silicon layer to the p-type amorphous silicon layer.

Claims

1. A photovoltaic device comprising:

a single-crystal substrate;

a substantially intrinsic amorphous semiconductor thin-film layer containing hydrogen and provided on the single-crystal substrate;

a doped amorphous semiconductor thin-film layer having a first and second region, the doped amorphous semiconductor thin-film layer containing hydrogen and provided on the intrinsic amorphous semiconductor thin-film layer; and

a hydrogen-diffusion reducing area provided between the doped amorphous semiconductor thin-film layer and the intrinsic amorphous semiconductor thin-film layer, the hydrogen-diffusion reducing area reducing hydrogen diffusion from the intrinsic amorphous semiconductor thin-film layer to the doped amorphous semiconductor thin-film layer, wherein;

the hydrogen-diffusion reducing area is an area formed in the vicinity of the interface between the doped amorphous semiconductor thin-film layer and the intrinsic amorphous semiconductor thin-film layer, the hydrogen-diffusion reducing area containing a higher concentration of hydrogen than that of the intrinsic amorphous semiconductor thin-film layer, and being doped with the same impurity as that for the doped amorphous semiconductor thin-film layer,

the doped amorphous semiconductor thin-film layer includes a positive gradient of hydrogen concentration from the first region to the second region, the second region being closer to the intrinsic amorphous semiconductor thin-film layer than the first region,

a concentration of the doped impurity in the hydrogen-diffusion reducing area is lower than that in the doped amorphous semiconductor thin-film layer,

a concentration of the doped impurity in the first region of the doped amorphous semiconductor thin-film layer is higher than the concentration of the doped impurity in the second region of the doped amorphous semiconductor thin-film layer, and

the concentration of hydrogen in the hydrogen-diffusion reducing area is more than that in the first region of the doped amorphous semiconductor thin-film layer and the intrinsic amorphous semiconductor thin-film layer.

2. A photovoltaic device comprising:

an n-type single-crystal silicon substrate;

a substantially intrinsic amorphous silicon layer containing hydrogen and provided on the single-crystal silicon substrate;

a p-type amorphous silicon layer having a first and second region, the p-type amorphous silicon layer containing hydrogen and provided on the intrinsic amorphous silicon layer; and

a hydrogen-diffusion reducing area provided between the p-type amorphous silicon layer and the intrinsic amorphous silicon layer and reducing hydrogen diffusion from the intrinsic amorphous silicon layer to the p-type amorphous silicon layer, wherein;

the hydrogen-diffusion reducing area is an area formed in the vicinity of the interface between the p-type amorphous silicon layer and the intrinsic amorphous silicon layer, the hydrogen-diffusion reducing area containing a higher concentration of hydrogen than that of the intrinsic amorphous silicon layer, and being doped with a p-type impurity,

the p-type amorphous silicon layer includes a positive gradient of hydrogen concentration from the first region to the second region, the second region being closer to the substantially intrinsic amorphous silicon layer than the first region,

a concentration of the p-type impurity in the hydrogen-diffusion reducing area is lower than that in the p-type amorphous silicon layer,

a concentration of the doped impurity in the first region of the p-type amorphous silicon layer is higher than the concentration of the doped impurity in the second region of the p-type amorphous silicon layer, and

the concentration of hydrogen in the hydrogen-diffusion reducing area is more than that in the first region of the p-type amorphous silicon layer and the substantially intrinsic amorphous silicon layer.

3. The photovoltaic device according to claim 2, wherein the p-type impurity is boron (B), and a concentration of boron (B) in the p-type amorphous silicon layer is greater than 2.0 at. %, and a concentrations of boron (B) in the hydrogen-diffusion reducing area is smaller than 1.0 at. %.