CIGS solar cell structure and method for fabricating the same
A method for manufacturing a CIGS thin film photovoltaic device includes forming a back contact layer on a substrate, forming an Se-rich layer on the back contact layer, forming a precursor layer on the Se-rich layer by depositing copper, gallium and indium resulting in a first interim structure, annealing or selenizing the first interim structure, thereby forming Cu/Se, Ga/Se or CIGS compounds along the interface between the back contact layer and the precursor layer and resulting in a second interim structure, and selenizing the second interim structure, thereby converting the precursor layer into a CIGS absorber layer on the back contact layer.
1. A method for manufacturing a thin film photovoltaic device comprising the steps of:
(a) forming a back contact layer on a substrate;
(b) forming an Se-rich layer on the back contact layer;
(c) forming a precursor layer on the Se-rich layer by depositing copper, gallium and indium resulting in a first interim structure;
(d) annealing the first interim structure, thereby forming Cu/Se, Ga/Se or CIGS compounds along the interface between the back contact layer and the precursor layer and resulting in a second interim structure; and
(e) selenizing the second interim structure, thereby converting the precursor layer into a CIGS absorber layer on the back contact layer.
2. The method of claim 1 , wherein the step (e) further includes sulfurizing the second interim structure concurrently with the selenizing step.
3. The method of claim 1 , wherein the forming of the Se-rich layer comprises depositing a film of Se.
4. The method of claim 1 , wherein the forming of the Se-rich layer comprises depositing a film of MoSe compound.
5. The method of claim 1 , wherein the forming of the Se-rich layer comprises depositing a film of InSe compound.
6. The method of claim 1 , wherein the forming of the Se-rich layer comprises depositing a film of CuSe compound.
7. The method of claim 1 , wherein the forming of the Se-rich layer comprises depositing a film of GaSe compound.
8. The method of claim 1 , wherein the annealing is conducted at a temperature in a range between 300° C. and 600° C.
9. The method of claim 1 , wherein the CIGS absorber layer has an Se concentration of 30 to 60 atomic % along its interface with the back contact layer.
10. The method of claim 1 , wherein the second interim structure is selenized in H 2 Se.
11. The method of claim 2 , wherein the second interim structure is sulferized in H 2 S.
12. A method for manufacturing a thin film photovoltaic device comprising the steps of:
(a) forming a back contact layer on a substrate;
(b) forming an Se-rich layer on the back contact layer;
(c) forming a precursor layer on the Se-rich layer by depositing copper, gallium, and indium resulting in a first interim structure;
(d) selenizing the first interim structure, thereby forming Cu/Se, Ga/Se or CIGS compounds along the interface between the back contact layer and the precursor layer and resulting in a second interim structure; and
(e) selenizing the second interim structure, thereby converting the precursor layer into a CIGS absorber layer on the back contact layer.
13. The method of claim 12 , wherein the step (e) further includes sulfurizing the second interim structure concurrently with the selenizing step.
14. The method of claim 12 , wherein the forming of the Se-rich layer comprises depositing a film of Se.
15. The method of claim 12 , wherein the forming of the Se-rich layer comprises depositing a film of MoSe compound.
16. The method of claim 12 , wherein the forming of the Se-rich layer comprises depositing a film of InSe compound.
17. The method of claim 12 , wherein the forming of the Se-rich layer comprises depositing a film of CuSe compound.
18. The method of claim 12 , wherein the forming of the Se-rich layer comprises depositing a film of GaSe compound.
19. The method of claim 12 , wherein the CIGS absorber layer has an Se concentration of 30 to 60 atomic % along its interface with the back contact layer.
20. The method of claim 12 , wherein the second interim structure is selenized in H 2 Se.