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 solar cell, comprising:
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.
2 . The solar cell of claim 1 , wherein the insulating aluminum zinc oxide layer has an aluminum content of 100 ppm to 2000 ppm.
3 . The solar cell of claim 2 , wherein the insulating aluminum zinc oxide layer has an aluminum content of 500 ppm to 1200 ppm.
4 . The solar cell of claim 1 , wherein the insulating aluminum zinc oxide layer has a thickness of 30 nm to 200 nm.
5 . The solar cell of claim 1 , wherein the insulating aluminum zinc oxide layer has a resistance of 100 Ω/□ to 10 6 Ω/□, and wherein the insulating aluminum zinc oxide layer is deposited by pulsed or non-pulsed DC sputtering.
6 . The solar cell of claim 5 , wherein the insulating aluminum zinc oxide layer has a resistance of 100 Ω/□ to 10 4 Ω/□.
7 . The solar cell of claim 1 , wherein the CIS based alloy material is selected from copper indium diselenide, copper indium gallium diselenide, or copper indium aluminum diselenide.
8 . A method of manufacturing a solar cell, comprising:
depositing a first electrode over a substrate;
depositing at least one p-type semiconductor absorber layer over the first electrode, the p-type semiconductor absorber layer comprising a copper indium selenide (CIS) based alloy material;
depositing an n-type semiconductor layer over the p-type semiconductor absorber layer to form a p-n junction;
depositing 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
depositing a second electrode over the n-type semiconductor layer, the second electrode being transparent and electrically conductive.
9 . The method of claim 8 , wherein the step of depositing the insulating aluminum zinc oxide comprises pulsed or non-pulsed DC sputtering or AC sputtering.
10 . The method of claim 9 , wherein the step of depositing the insulating aluminum zinc oxide layer comprises pulsed or non-pulsed DC sputtering an aluminum doped zinc oxide target having an aluminum content of 100 ppm to 5000 ppm.
11 . The method of claim 9 , wherein the step of depositing the insulating aluminum zinc oxide layer comprises pulsed or non-pulsed DC sputtering an aluminum doped zinc oxide target having an aluminum content of 100 ppm to 2000 ppm.
12 . The method of claim 8 , wherein the step of depositing the insulating aluminum zinc oxide layer comprises pulsed or non-pulsed DC sputtering in a sputter atmosphere containing 1 to 50 volume percent of oxygen-containing gas.
13 . The method of claim 12 , wherein the step of the insulating aluminum zinc oxide layer comprises pulsed or non-pulsed DC sputtering in a sputter atmosphere comprising argon gas with 5 to 10 volume percent of the oxygen-containing gas.
14 . The method of claim 13 , wherein the oxygen-containing gas is O 2 or H 2 O.
15 . The method of claim 8 , wherein the insulating aluminum zinc oxide layer has a thickness of 30 nm to 200 nm.
16 . The method of claim 8 , wherein the CIS based alloy material is selected from copper indium diselenide, copper indium gallium diselenide, copper indium aluminum diselenide, or combination thereof.
17 . The method of claim 8 , wherein the steps of depositing the first electrode, depositing the at least one p-type semiconductor absorber layer, depositing the n-type semiconductor layer, depositing the insulating zinc oxide layer, and depositing the second electrode are performed by DC or AC sputtering in a same sputtering apparatus without breaking vacuum.
18 . 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/□.
19 . A method of claim 18 , 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/□.
20 . A method of claim 18 , 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.
21 . A sputtering target configured for DC or AC sputtering, comprising aluminum doped zinc oxide having an aluminum content of 100 ppm to 5000 ppm.
22 . The sputtering target of claim 21 , 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.