# US 7,744,705 B2 · Group I-III-VI quaternary or higher alloy semiconductor films

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- Number: US 7,744,705 B2
- Document ID: US7744705B2
- Status: Granted
- Kind: B2
- Application number: 10/568,229
- Filed: 2004-08-13
- Published: 2006-10-05
- Granted: 2010-06-29
- Earliest claimed: 2003-08-14
- Assignees: University of Johannesburg
- Inventors: Vivian Alberts
- Web page: https://patentgrep.com/patent/US7744705B2

## CPC

- H10F 77/126: {comprising only Group I-III-VI chalcopyrite materials, e.g. CuInSe2, CuGaSe2 or CuInGaSe2 [CIGS]}
- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- H10F 71/128: {Annealing}
- Y02E 10/541: CuInSe2 material PV cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

This invention relates to group IB-IIIA. VIA quaternary or higher alloys. More particularly, this invention relations to group IB-IIIA-VIA quaternary or pentenary alloys which are suitable for use as semiconductor films. More specifically, the invention relates to quaternary or pentenary alloys which are substantially homogeneous and are characterized by an x-ray diffraction pattern (XRD) having a main [112] peak at a 2θ angle (2θ(112)) of from 26° to 28° for Cu radiation at 40 kV, wherein a glancing incidence x-ray diffraction pattern (GIXRD) for a glancing angle of from 0.2° to 10° reflects an absolute shift in the 2θ(112) angle of less than 0.06°.

## Claims

### Claim 1

A quaternary or higher group IB-IIIA-VIA alloy having the general formula (I):
A(B1-xCx)(D1-yEy)2 (I)
wherein:
A is Cu;
B is In;
C is Ga;
D is a first group VIA element (hereinafter referred to as VIA1);
E is a second group VIA element (hereinafter referred to as VIA2); and
each of x and y independently are from 0 to 1, provided that both x and y are not zero or one at the same time and if x is zero y must be smaller than 1 and if y is zero x must be smaller than one;
and the alloy being characterized by an x-ray diffraction pattern (XRD) having a main [112] peak at a 2θ angle (2θ(112)) of from 26° to 28° for Cu radiation at 40 kV, wherein a glancing incidence x ray diffraction pattern (GIXRD) for glancing angles at 0.5°, 1°, 2°, 5°, and 10° reflects an absolute shift in the 2θ(112) angle of less than 0.06° between any one of such glancing angles and all of the other of such angles considered one at a time.

### Claim 2 (depends on 1)

The alloy of claim 1, wherein the alloy has a crystal structure comprising a lattice of unit cells, wherein all crystallographic planes of the unit cells show a variance in d-spacing of less than 0.01 Å.

### Claim 3 (depends on 1)

The alloy of claim 1, wherein the element concentration of elements A, B, C, D and E, as characterised by XPS depth profiling, is substantially uniform through the alloy.

### Claim 4 (depends on 1)

The alloy of claim 1, wherein D is Se and E is S, the alloy having a formula (II):
Cu(In1-xGax)(Se1-ySy)2 (II),
with x and y both being larger than 0 but smaller than 1.

### Claim 5 (depends on 4)

The alloy of claim 4, wherein x is from 0.25 to 0.3 and y is from 0.05 to 0.8.

### Claim 6 (depends on 4)

The alloy of claim 4, wherein the x-ray diffraction pattern (XRD) has a main [112] peak at a 2θ angle (2θ(112)) of from 26.9° to 28° for Cu radiation at 40 kV, taken at a d-spacing of from 3.3117 Å to 3.1840 Å.

### Claim 7 (depends on 4)

The alloy of claim 4, wherein the absolute shift in the 2θ(112) angle is less than 0.01°.

### Claim 8 (depends on 4)

The alloy of claim 4, wherein the alloy has a crystal structure comprising a lattice of unit cells, wherein all crystallographic planes of the unit cells show a variance in d-spacing of less than 0.001 Å.

### Claim 9 (depends on 6)

The alloy of claim 6, wherein the main [112] peak is from a 2θ angle of from 27.0° to 27.5°.

### Claim 10 (depends on 6)

The alloy of claim 6, wherein the main [112] peak is substantially symmetrical.

### Claim 11 (depends on 4)

The alloy of claim 4, wherein the alloy has a band gap that can be shifted from 1 eV to 2.4 eV.

### Claim 12 (depends on 11)

The alloy of claim 11, wherein the alloy has a band gap that can be shifted from 1.1 eV to 1.5 eV.

### Claim 13 (depends on 4)

The alloy of claim 4, wherein the S content, as expressed by the molar ratio of S/(S+Se), is from 0.05 to 0.7.

### Claim 14 (depends on 1)

The alloy of claim 1, wherein, D is Se and y =0, the alloy having the general formula (III):
Cu(In1-xGax)Se2 (III)
and x is larger than 0 but smaller than 1.

### Claim 15 (depends on 14)

The alloy of claim 14, wherein x is from 0.25 and 0.3.

### Claim 16 (depends on 14)

The alloy of claim 14, wherein the alloy has a crystal structure comprising a lattice of unit cells, wherein all crystallographic planes of the unit cells show a variance in d-spacing of less than 0.006 Å.

### Claim 17 (depends on 14)

The alloy of claim 14, wherein the x-ray diffraction pattern (XRD) has a main [112] peak at a 2θ angle (2θ(112)) of from 26.80° to 27.0° for Cu radiation at 40 kV, taken at a d-spacing of from 3.3236 Å to 3.2990 Å.

### Claim 18 (depends on 14)

The alloy of claim 14, wherein the GIXRD reflects an absolute shift in the 2θ(112) angle of less than 0.05° between any one of such glancing angles and all of the other of such angles considered one at a time.

### Claim 19 (depends on 17)

The alloy of claim 17, wherein the main (112] peak lies from a 2θ angle of from 26.85° to 26.9°.

### Claim 20 (depends on 17)

The alloy of claim 17, wherein the main (112] peak is substantially symmetrical.

### Claim 21 (depends on 14)

The alloy of claim 14, wherein the alloy has a band gap which can be shifted from 1.1 eV to 1.2 eV.

### Claim 22 (depends on 21)

The alloy of claim 21, wherein the alloy has a band gap which can be shifted from 1.15 eV to 1.18 eV.

### Claim 23 (depends on 14)

The alloy of claim 14, wherein the Ga content, as expressed by the molar ratio of Ga/(Ga+In) is from 0.25 to 0.3.

### Claim 24 (depends on 1)

The alloy of claim 1, wherein A is Cu, B is In, D is Se, E is S and x=0 and has the general formula (IV):
CuIn(Se1-ySy)2 (IV)
and y is larger than 0 but smaller than 1.

### Claim 25 (depends on 24)

The alloy of claim 24, wherein y is from 0.1 and 0.5.

### Claim 26 (depends on 24)

The alloy of claim 24, wherein the alloy has a crystal structure comprising a lattice of unit cells, wherein all crystallographic planes of the unit cells show a variance in d-spacing of less than 0.007 Å.

### Claim 27 (depends on 24)

The alloy of claim 24, wherein the x-ray diffraction pattern (XRD) has a main (112] peak at a 2θ angle (2θ(112)) of from 26.80° to 27.3° for Cu radiation at 40 kV, taken at a d-spacing of from 3.3236 Å to 3.2640 Å.

### Claim 28 (depends on 24)

The alloy of claim 24, wherein the GIXRD for a glancing angle of from 0.2° to 10° reflects an absolute shift in the 2θ(112) angle of less than 0.06°.

### Claim 29 (depends on 27)

The alloy of claim 27, wherein the main (112] peak lies from a 2θ angle of from 27.0° to 27.2°.

### Claim 30 (depends on 24)

The alloy of claim 24, wherein the alloy has a band gap which can be shifted from 1.05 eV to 1.23 eV.

### Claim 31 (depends on 30)

The alloy of claim 30, wherein the alloy has a band gap which can be shifted from 1.15 eV to 1.20 eV.

### Claim 32 (depends on 24)

The alloy of claim 24, wherein the S content, as expressed by the ratio of S/(S+Se) lies from 0.1 and 0.5.

### Claim 33 (depends on 1)

A semiconductor film comprising a film of an alloy of claim 1.

### Claim 34 (depends on 33)

The semiconductor film of claim 33, wherein said film is deposited onto a substrate which serves as a support for the alloy.

### Claim 35 (depends on 33)

The semiconductor film according to claim 33, wherein the alloy is in the form of a film having a thickness of 1.5 to 2.0 μm.

### Claim 36 (depends on 1)

A photovoltaic cell including a semiconductor film of an alloy of claim 1.

### Claim 37 (depends on 36)

The photovoltaic cell according to claim 36, wherein the photovoltaic cell has a conversion efficiency of from 8 to 15%.

### Claim 38

A pentenary alloy having the general formula:
Cu(In1-xGax)(Se1-ySy)2
wherein x is between 0 and 1 and y is between 0 and 1;
the alloy being characterized by an x-ray diffraction pattern (XRD) having a main [112] peak at a 2θ angle (2θ(112)) of from 26° to 28° for Cu radiation at 40 kV, wherein a glancing incidence x ray diffraction pattern (GIXRD) for glancing angles at 0.5°, 1°, 2°, 5°, and 10° reflects an absolute shift in the 2θ(112) angle of less than 0.01° between any one of such glancing angles and all of the other of such angles considered one at a time.

### Claim 39 (depends on 38)

The pentenary alloy of claim 38, wherein x is from 0.25 to 0.3 and y is from 0.05 to 0.5.