DOPED BUFFER LAYER
A solar cell with a doped buffer layer includes silicon and tin.
1 . A photovoltaic device comprising:
a substrate;
a barrier layer adjacent to the substrate;
a transparent conductive oxide layer adjacent to the barrier layer; and
a buffer layer adjacent to the transparent conductive oxide layer, wherein the buffer layer comprises silicon-doped tin oxide.
2 . The photovoltaic device of claim 1 , wherein the weight percentage of silicon to tin in the buffer layer is between about 0.1% and about 20%.
3 . The photovoltaic device of claim 2 , wherein the weight percentage of silicon to tin in the buffer layer is between about 0.5% and about 10%.
4 . The photovoltaic device of claim 2 , wherein the weight percentage of silicon to tin in the buffer layer is between about 0.1% and about 2%.
5 . The photovoltaic device of claim 1 , wherein the transparent conductive oxide layer comprises cadmium oxide.
6 . The photovoltaic device of claim 1 , wherein the transparent conductive oxide layer comprises cadmium tin oxide.
7 . The photovoltaic device of claim 1 , wherein the substrate comprises glass.
8 . The photovoltaic device of claim 1 , further comprising a semiconductor bi-layer adjacent to the transparent conductive oxide layer, wherein the semiconductor bi-layer comprises a semiconductor absorber layer and a semiconductor window layer.
9 . The photovoltaic device of claim 8 , wherein the semiconductor absorber layer comprises cadmium telluride.
10 . The photovoltaic device of claim 8 , wherein the semiconductor window layer comprises cadmium sulfide.
11 . The photovoltaic device of claim 1 , wherein the barrier layer comprises silicon oxide.
12 . The photovoltaic device of claim 1 , wherein the thicknesses of the buffer layer is between about 500 angstrom and about 5000 angstrom.
13 . The photovoltaic device of claim 12 , wherein the thicknesses of the buffer layer is between about 1000 angstrom and about 2500 angstrom.
14 . A method of manufacturing a photovoltaic device comprising the steps of:
depositing a barrier layer adjacent to a substrate;
depositing a transparent conductive oxide layer adjacent to the barrier layer; and
depositing a buffer layer adjacent to the transparent conductive oxide layer, wherein the buffer layer comprises silicon-doped tin oxide.
15 . The method of claim 14 , further comprising depositing a semiconductor bi-layer adjacent to the buffer layer, wherein the semiconductor bi-layer comprises a semiconductor absorber layer and a semiconductor window layer.
16 . The method of claim 14 , wherein depositing the buffer layer comprises sputtering a sputter target.
17 . The method of claim 16 , wherein the sputtering comprises reactive sputtering.
18 . The method of claim 16 , wherein the sputter target comprises tin and silicon.
19 . The method of claim 18 , wherein the sputter target has a silicon weight percentage ranging from about 0.1% to about 20%.
20 . The method of claim 18 , wherein the sputter target has a silicon weight percentage ranging from about 0.5% to about 10%.
21 . The method of claim 18 , wherein the sputter target has a silicon weight percentage ranging from about 0.1% to about 2%.
22 . The method of claim 16 , wherein the sputtering comprises reactive sputtering from a rotary target comprising tin and silicon, wherein the sputtering occurs in the presence of oxygen in a sputter chamber.
23 . The method of claim 14 , wherein depositing the transparent conductive oxide layer comprises reactive sputtering from a doped target.
24 . The method of claim 14 , further comprising an annealing step to anneal the transparent conductive oxide.
25 . A sputter target comprising:
a sputter material containing silicon and tin; and
a backing tube, wherein the sputter material is connected to the backing tube to form a sputter target.
26 . The sputter target of claim 25 comprising a silicon weight percentage of about 0.1% to about 20%.
27 . The sputter target of claim 26 comprising a silicon weight percentage of about 0.5% to about 10%.
28 . The sputter target of claim 26 comprising a silicon weight percentage of about 0.1% to about 2%.
29 . The sputter target of claim 25 , further comprising a bonding layer bonding the sputter material and the backing tube.
30 . The sputter target of claim 25 , wherein the backing tube comprises stainless steel.
31 . The sputter target of claim 25 , wherein the sputter target is configured to use in reactive sputtering process.
32 . A method of manufacturing a rotary sputter target configured for use in manufacture of photovoltaic device comprising the steps of:
forming a sputter material comprising tin and silicon; and
attaching the sputter material to a backing tube to form a sputter target.
33 . The method of claim 32 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a thermal spray forming process.
34 . The method of claim 32 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a plasma spray forming process.
35 . The method of claim 32 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a powder metallurgy process.
36 . The method of claim 35 , wherein the powder metallurgy comprises hot press process.
37 . The method of claim 35 , wherein the powder metallurgy comprises isostatic process.
38 . The method of claim 32 , wherein the step of attaching the sputter material to a backing tube to form a sputter target comprises a flow forming process.
39 . The method of claim 32 , wherein the sputter material has a silicon weight percentage ranging from about 0.1% to about 20%.
40 . The method of claim 39 , wherein the sputter material has a silicon weight percentage ranging from about 0.5% to about 10%.
41 . The method of claim 39 , wherein the sputter material has a silicon weight percentage ranging from about 0.1% to about 2%.
42 . The method of claim 32 , wherein the step of attaching the sputter material to the backing tube comprises bonding the sputtering material to the backing tube with a bonding layer.
43 . The method of claim 32 , wherein the backing tube comprises stainless steel.
44 . The method of claim 32 , wherein the sputter target is configured to use in reactive sputtering process.