Composition and Method of Forming an Insulating Layer in a Photovoltaic Device
A solar cell includes a first electrode located over a substrate, at least one p-type semiconductor absorber layer located over the first electrode, the p-type semiconductor absorber layer comprising a copper indium selenide (CIS) based alloy material, an n-type semiconductor layer located over the p-type semiconductor absorber layer, an insulating aluminum zinc oxide layer located over the n-type semiconductor layer, the insulating aluminum zinc oxide having an aluminum content of 100 ppm to 5000 ppm and a second electrode over the insulating aluminum layer, the second electrode being transparent and electrically conductive. The insulating aluminum zinc oxide having an aluminum content of 100 ppm to 5000 ppm, may be deposited by pulsed DC, non-pulsed DC, or AC sputtering from an aluminum doped zinc oxide having an aluminum content of 100 ppm to 5000 ppm.
1 . A method of depositing an insulating aluminum zinc oxide layer, comprising pulsed or non-pulsed DC sputtering an aluminum doped zinc oxide target having an aluminum content of 100 ppm to 5000 ppm, wherein the insulating aluminum zinc oxide layer has a resistance of 100 Ω/□ to 10 6 Ω/□.
2 . A method of claim 1 , wherein the aluminum doped zinc oxide target has an aluminum content of 100 ppm to 2000 ppm, and wherein the insulating aluminum zinc oxide layer has a resistance of 100 Ω/□ to 10 4 Ω/□.
3 . A method of claim 1 , wherein the step of pulsed or non-pulsed DC sputtering is conducted in a sputter atmosphere comprising argon gas with 5 to 10 volume percent of oxygen-containing gas.
4 . A sputtering target configured for DC or AC sputtering, comprising aluminum doped zinc oxide having an aluminum content of 100 ppm to 5000 ppm.
5 . The sputtering target of claim 4 , wherein:
the sputtering target is mounted in a pulsed or non-pulsed DC sputtering system; and
the aluminum doped zinc oxide has an aluminum content of 100 ppm to 2000 ppm.