Photovoltaic device and method for making

1. A method to make a photovoltaic device comprising:

disposing a transparent conductive layer on a substrate;

disposing a transparent window layer on the transparent conductive layer;

disposing a first semiconducting layer adjacent to the transparent window layer;

wherein disposing the transparent window layer comprises:

providing a target comprising a semiconductor material within an environment comprising oxygen, wherein the semiconductor material comprises cadmium and sulfur;

applying a plurality of direct current (DC) pulses to the target to create a pulsed DC plasma;

sputtering the target with the pulsed DC plasma to eject a material comprising cadmium and sulfur into the plasma; and

depositing a film comprising the material onto a substrate.

2. The method of claim 1 , wherein the transparent window layer further comprises zinc telluride, zinc selenide, cadmium selenide, cadmium sulfur oxide, and or copper oxide.

3. The method of claim 1 , wherein the transparent window layer comprises cadmium sulfide.

4. The method of claim 1 , wherein the transparent window layer comprises CdS 1-y O y where y varies from 0.01 to 0.5.

5. The method of claim 1 , wherein the transparent window layer comprises a gradient of oxygen concentration within the transparent window layer.

6. The method of claim 1 , wherein the transparent window layer has a band gap in a range from about 2.3 electron Volts to about 3.1 electron Volts.

7. The method of claim 1 , wherein the transparent window layer comprises oxygen in a range from about 0.1 atomic percent to about 50 atomic percent.

8. The method of claim 1 , wherein the transparent window layer has a thickness in a range from about 5 nanometers to about 250 nanometer.