Monolithic multi-junction solar cells with amorphous silicon and CIS and their alloys

• US 6,121,541 A
• Filed: 07/28/1997
• Issued: 09/19/2000
• Est. Priority Date: 07/28/1997
• Status: Expired due to Term

• Current Assignee: BP Solar International Incorporated (BP PLC)
• Original Assignee: BP SOLAREX (BP PLC)
• Inventors: Arya, Rajeewa R.
• Primary Examiner(s): Robinson, Ellis
• Assistant Examiner(s): Miggins, Michael C.
• Application Number:
  US08/900,160
• Time in Patent Office: 1,149 Days
• Field of Search: 136/255, 136/258, 136/261, 136/262, 136/264, 136/249, 257/184, 257/200
• US Class Current: 136/255
• 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 31/078 including different types of potential barriers provided for in two or more of groups H01L31/062 - H01L31/075
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Efficient broader spectrum monolithic solar cells are produced by coupling a CIS or CIGS polycrystalline semiconductor to an amorphous silicon semiconductor. Coupling can be accomplished with a n-type conductor, such as cadmium sulfide or microcrystalline n-doped amorphous silicon. Cadmium sulfide can be deposited on the CIS or CIGS polycrystalline semiconductor by solution growth, sputtering or evaporation. A transparent conductive oxide can be deposited on the cadmium sulfide by low pressure chemical vapor deposition. The microcrystalline n-doped amorphous silicon and the amorphous silicon semiconductor can be deposited by enhanced plasma chemical vapor deposition. The amorphous silicon can comprise: hydrogenated amorphous silicon, hydrogenated amorphous silicon carbon, or hydrogenated amorphous silicon germanium. Triple junction solar cells can be produced with an amorphous silicon front cell, an amorphous silicon germanium middle cell, and a CIS or CIGS polycrystalline back cell, on a substrate.

Claims

1. A monolithic solar cell, comprising:

a vitreous substrate comprising glass;

a first semiconductor comprising a copper indium polycrystalline semiconductor, said copper indium polycrystalline semiconductor disposed on said vitreous substrate comprising glass, and said copper indium polycrystalline semiconductor being selected from the group consisting of copper indium diselenide (CIS) and copper indium gallium selenide (CIGS);

a second semiconductor comprising an n-i-p or p-i-n amorphous silicon-containing thin film semiconductor, said second semiconductor comprising said n-i-p or p-i-n amorphous silicon-containing thin film semiconductor disposed above said first semiconductor comprising said copper indium polycrystalline semiconductor;

an n-type conductor comprising microcrystalline n-doped amorphous silicon or cadmium sulfide, said n-type conductor positioned between and coupling said first semiconductor comprising said copper indium polycrystalline semiconductor and said second semiconductor comprising said n-i-p or p-i-n amorphous silicon-containing thin film semiconductor; and

said vitreous substrate, copper indium polycrystalline semiconductor, n-i-p or p-i-n amorphous silicon-containing thin film semiconductor, and said n-type conductor comprising said microcrystalline n-doped amorphous silicon or cadmium sulfide, cooperating with each other for providing a monolithic solar cell.

2. A monolithic solar cell in accordance with claim 1 wherein:

a rear contact is positioned between and connected to at least a portion of said first semiconductor comprising said copper indium polycrystalline semiconductor and said vitreous substrate;

said rear contact is selected from the group consisting of molybdenum, aluminum, silver, platinum, zinc oxide, and tin oxide;

a front contact is positioned on and connected to at least a portion of said second semiconductor comprising said n-i-p or p-i-n amorphous silicon-containing thin film semiconductor, said front contact comprising a transparent conductive oxide selected from the group consisting of zinc oxide and tin oxide; and

said n-i-p or p-i-n amorphous silicon-containing thin film conductor is selected from the group consisting of hydrogenated amorphous silicon, hydrogenated amorphous silicon carbon, and hydrogenated amorphous silicon germanium.

3. A monolithic solar cell in accordance with claim 1 wherein:

said n-type conductor comprises cadmium sulfide and a transparent conductive oxide positioned between and connected to said cadmium sulfide and said amorphous silicon-containing thin film semiconductor;

said transparent conductive oxide of said n-type conductor is selected from the group consisting of zinc oxide and tin oxide; and

said transparent conductive oxide of said n-type conductor is positioned between and spaced from said front contact and said rear contact.

4. A monolithic solar cell in accordance with claim 1 wherein:

said solar cell comprises a monolithic triple junction solar cell;

said second semiconductor comprising said amorphous silicon-containing thin film semiconductor is a n-i-p semiconductor comprising hydrogenated amorphous silicon germanium; and

said triple junction solar cell includes a third semiconductor comprising hydrogenated amorphous silicon germanium.

5. A monolithic triple-junction solar cell, comprising:

a glass substrate;

a rear contact positioned on said glass substrate, said rear contact being selected from the group consisting of molybdenum, aluminum, silver, zinc oxide, and tin oxide;

a polycrystalline back cell positioned on said rear contact, said polycrystalline back cell having a bandgap ranging from 1 eV to 1.2 eV, said polycrystalline back cell being connected to said rear contact on said glass substrate, said polycrystalline back cell being selected from the group consisting of copper indium diselenide (CIS) and copper indium gallium selenide (CIGS), and said copper indium gallium selenide comprising 0.1% to 24% by weight gallium;

a microcrystalline n-layer positioned on said polycrystalline back cell, said microcrystalline n-layer comprising microcrystalline n-doped silicon;

an intermediate n-i-p amorphous silicon cell positioned on said microcrystalline n-layer, said intermediate n-i-p amorphous silicon cell comprising hydrogenated amorphous silicon germanium with a bandgap ranging from 1.4 eV to 1.6 eV;

a front n-i-p amorphous silicon cell positioned on said intermediate n-i-p amorphous silicon cell, said front n-i-p amorphous silicon cell comprising hydrogenated amorphous silicon with a bandgap of 1.4 eV; and

a front contact positioned on and operatively connected to said front n-i-p amorphous silicon cell, said front contact comprising a transparent conductive oxide selected from the group consisting of zinc oxide and tin oxide.