Process for preparing group Ib-IIIa-VIa semiconducting films

• US 5,674,555 A
• Filed: 11/30/1995
• Issued: 10/07/1997
• Est. Priority Date: 11/30/1995
• Status: Expired due to Term

• Current Assignee: University of Delaware
• Original Assignee: University of Delaware
• Inventors: Hichri, Habib, Birkmire, Robert W., Marudachalam, Matheswaran, Schultz, Jerold M.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US08/564,957
• Time in Patent Office: 677 Days
• Field of Search: 427/74, 427/76, 437/5, 437/234, 437/247, 136/264, 136/265
• US Class Current: 427/76
• CPC Class Codes: H01L 21/02568 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 21/02614 Transformation of metal, e.g. oxidation, nitridation
• 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: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y10S 438/93 Ternary or quaternary semiconductor comprised of elements from three different groups, e.g. I-III-V

Abstract

Methods are provided for the production of supported monophasic group I-III-VI semiconductor films. In the subject methods, a substrate is coated with group I and III elements and then contacted with a reactive group VI element containing atmosphere under conditions sufficient to produce a substrate coated with a composite of at least two different group I-III-IV alloys. The resultant composite coated substrate is then annealed in an inert atmosphere under conditions sufficient to convert the composite coating to a monophasic group I-III-VI semiconductor film. The resultant supported semiconductor films find use in photovoltaic applications, particularly as absorber layers in solar cells.

Claims

1. A method for producing supported group Ib-IIIa-VIa semiconductor films, comprising the steps of:

a) coating a substrate with group Ib and IIIa elements to produce a coated substrate;

b) heating said coated substrate in the presence of a reactive group VIa element containing atmosphere under conditions sufficient to produce a composite coated substrate, wherein said composite comprises at least two different group Ib-IIIa-VIa alloys;

c) annealing said composite coated substrate in an inert atmosphere to convert said composite coating to a monophasic group Ib-III-VIa semiconductor film;

whereby a supported group Ib-IIIa-VIa semiconductor film is produced.

2. The method according to claim 1, wherein said group IIIa element comprises Ga in combination with an additional group IIIa element.

3. The method according to claim 1, wherein said method further comprises contacting said supported semiconductor film with a reactive group VIa element containing atmosphere under conditions sufficient to increase the group VIa element content of said supported semiconductor film.

4. A method for producing a group Ib-Ga-IIIa-Se semiconductor film, comprising the steps of:

a) coating a substrate with Ga, a group Ib, and an additional group IIIa element to produce a coated substrate;

b) heating said coated substrate in the presence of a selenium containing atmosphere at a temperature ranging from about 400°

to 450°

C. for about 80 to 100 min to produce a composite coated substrate, wherein said composite comprises at least two different group Ib-IIIa-Se alloys;

c) annealing said composite coated substrate in an inert atmosphere at a temperature ranging from about 500°

to 600°

C. for about 60 to 120 min to produce a monophasic group Ib-Ga-IIIa-Se semiconductor film;

whereby a supported group Ib-Ga-IIIa-Se semiconductor film is produced.

5. The method according to claim 4, wherein said method further comprises contacting said supported semiconductor film with a reactive selenium containing atmosphere under conditions sufficient to increase the selenium content of said supported semiconductor film.

6. The method according to claim 4, wherein said group lb element is selected from the group consisting of Cu, Ag, and Au.

7. The method according to claim 4, wherein said additional group IIIa element is selected from the group consisting of In, Al, and Tl.

8. The method according to claim 4, wherein said Se containing atmosphere comprises at least one of H2Se and elemental Se.

9. A method for producing a supported CuIn_1-x Ga_x Se₂ semiconductor film, wherein x ranges from 0.1 to 0.9 comprising the steps of:

a) coating a substrate with Cu, In, and Ga to produce a coated substrate;

b) heating said coated substrate in the presence of a reactive selenium containing atmosphere at a temperature ranging from about 400°

to 450°

C. for about 80 to 100 min to produce a composite coated substrate, where said composite comprises CuInSe₂ and CuGaSe₂ alloys;

c) annealing said composite coated substrate in an inert atmosphere at a temperature ranging from about 500°

to 650°

C. for about 60 to 120 min to produce a monophasie group CuIn_1-x Ga_x Se₂ layer;

whereby a supported CuIn_1-x Ga_x Se₂ semiconductor film is produced.

10. The method according to claim 9 wherein said method further comprises contacting said supported semiconductor film with a reactive selenium containing atmosphere under conditions sufficient to increase the selenium content of said supported semiconductor film.

11. The method according to claim 10, wherein said Se containing atmosphere comprises at least one of H₂ Se and elemental Se.