Cadmium telluride thin film photovoltaic devices and methods of manufacturing the same
View Patent ↗Methods for manufacturing a cadmium telluride based thin film photovoltaic device are generally disclosed. The method can include sputtering a resistive transparent layer on a transparent conductive oxide layer from an alloy target including zinc from about 5% by weight and about 33% by weight and tin. The method can also include forming a cadmium sulfide layer on the resistive transparent layer, forming a cadmium telluride layer on the cadmium sulfide layer, and forming a back contact layer on the cadmium telluride layer. Cadmium telluride thin film photovoltaic devices are also generally disclosed including a resistive transparent layer having a mixture of zinc oxide and tin oxide having a zinc oxide concentration between about 5% and about 33% by mole fraction.
1. A cadmium telluride thin film photovoltaic device, comprising:
a glass superstrate;
a transparent conductive oxide layer on the glass superstrate;
a resistive transparent layer on the transparent conductive oxide layer, wherein the resistive transparent layer comprises Zn x Sn 1-x O 2-x , where 0.05<x<0.33;
a cadmium sulfide layer on the resistive transparent layer;
a cadmium telluride layer on the cadmium sulfide layer; and,
a back contact on the cadmium telluride layer.
2. The cadmium telluride thin film photovoltaic device as in claim 1 , wherein the resistive transparent layer comprises Zn x Sn 1-x O 2-x , where 0.1<x<0.2.
3. The cadmium telluride thin film photovoltaic device as in claim 1 , wherein the resistive transparent layer consists of Zn x Sn 1-x O 2-x , where 0.05<x<0.33.
4. A method for manufacturing a cadmium telluride based thin film photovoltaic device, the method comprising:
sputtering a resistive transparent layer on a transparent conductive oxide layer from an alloy target, wherein the alloy target comprises zinc and tin, and wherein the resistive transparent layer comprises Zn x Sn 1-x O 2-x , where 0.05<x<0.33;
forming a cadmium sulfide layer on the resistive transparent layer;
forming a cadmium telluride layer on the cadmium sulfide layer; and,
forming a back contact layer on the cadmium telluride layer.
5. The method as in claim 4 , wherein the alloy target comprises elemental zinc from about 5% by weight to about 20% by weight.
6. The method as in claim 4 , wherein the alloy target comprises elemental zinc from about 10% by weight to about 20% by weight.
7. The method as in claim 4 , wherein the resistive transparent layer is sputtered at a temperature between about 15° C. and about 100° C.
8. The method as in claim 4 , wherein the resistive transparent layer is sputtered at a temperature between about 100° C. and about 300° C.
9. The method as in claim 4 , wherein the resistive transparent layer is DC sputtered from the alloy target in an oxygen atmosphere, wherein the alloy target is a metal alloy target comprising elemental zinc from about 3% by weight to about 22% by weight and elemental tin.
10. The method as in claim 9 , wherein the metal alloy target consists of elemental zinc from about 5% by weight to about 20% by weight and elemental tin.
11. The method as in claim 9 , wherein the metal alloy target consists of elemental zinc from about 10% by weight to about 20% by weight and elemental tin.
12. The method as in claim 9 , wherein the oxygen atmosphere comprises about 99% oxygen or greater.
13. The method as in claim 9 , wherein the oxygen atmosphere has a pressure between about 1 mTorr and about 20 mTorr.
14. The method as in claim 9 , wherein the oxygen atmosphere has a pressure between about 5 mTorr and about 10 mTorr.
15. The method as in claim 4 , wherein the resistive transparent layer is RF sputtered from the alloy target, wherein the alloy target is a ceramic alloy target comprising zinc oxide and tin oxide with the zinc oxide having a mole fraction between about 5% and about 33%.
16. The method as in claim 15 , wherein the ceramic alloy target comprises zinc oxide and tin oxide with the zinc oxide having a mole fraction between about 5% and about 20%.
17. The method as in claim 15 , wherein the ceramic alloy target consists of zinc oxide and tin oxide with the zinc oxide having a mole fraction between about 10% and about 20%.
18. The method as in claim 4 , wherein the resistive transparent layer has a thickness between about 0.01 μm and about 1 μm.
19. The method as in claim 4 , wherein the resistive transparent layer has a thickness between about 0.1 μm to about 0.5 μm.