PHOTOVOLTAIC DEVICE INCLUDING DOPED LAYER
A photovoltaic cell with a doped buffer layer includes a metal oxide and a dopant.
1 . A structure 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 a metal oxide doped with a Group V element, or doped with an anion.
2 . The structure of claim 1 , wherein the metal oxide comprises a material selected from the group consisting of tin oxide, zinc oxide, and zinc tin oxide.
3 . The structure of claim 1 , wherein the Group V element comprises a material selected from the group consisting of antimony, arsenic, vanadium, niobium, and tantalum.
4 . The structure of claim 1 , wherein the concentration of the Group V element or anion in the buffer layer is between 10 15 and 10 20 atoms/cm 3 .
5 . The structure of claim 1 , wherein the buffer layer comprises a uniform equivalent thickness between 100 angstrom and 5000 angstrom.
6 . The structure of claim 1 , wherein the buffer layer comprises more than one deposited film.
7 . The structure of claim 1 , wherein the buffer layer comprises two layers doped with different Group V elements.
8 . The structure of claim 1 , wherein the buffer layer is annealed.
9 . The structure of claim 1 , wherein the buffer layer comprises an oxygen vacancy.
10 . The structure of claim 1 , wherein the substrate comprises a material selected from the group consisting of soda lime glass and solar float glass; the barrier layer comprises a material selected from the group consisting of silicon oxide, silicon dioxide, silicon aluminum oxide, silicon oxynitride, and silicon aluminum oxynitride; and the transparent conductive oxide layer comprises a material selected from the group consisting of fluorine-doped tin oxide, indium tin oxide, cadmium stannate, and zinc aluminum oxide.
11 . The structure of claim 1 , wherein the anion comprises a halide ion.
12 . The structure of claim 11 , wherein the halide ion is selected from the group consisting of a chloride ion and a fluoride ion.
13 . A method of manufacturing a structure comprising the steps of:
depositing a barrier layer adjacent to a substrate;
depositing a transparent conductive oxide layer adjacent to the barrier layer; and
forming a buffer layer adjacent to the transparent conductive oxide layer, wherein the buffer layer comprises a metal oxide doped with a Group V element or an anion.
14 . The method of claim 13 , wherein the step of forming a buffer layer adjacent to the transparent conductive oxide layer comprises sputtering a sputter target to form the buffer layer.
15 . The method of claim 14 , wherein the step of sputtering a sputter target comprises sputtering a sputter target comprising a metal and the Group V element.
16 . The method of claim 14 , wherein the step of sputtering a sputter target comprises sputtering the sputter target in an environment comprising oxygen to control an oxygen vacancy in the buffer layer.
17 . The method of claim 13 , wherein the step of forming a buffer layer adjacent to the transparent conductive oxide layer comprises physical vapor deposition.
18 . The method of claim 17 , wherein the physical vapor deposition comprises electron beam evaporation.
19 . The method of claim 13 , wherein the step of forming a buffer layer adjacent to the transparent conductive oxide layer comprises chemical vapor deposition
20 . The method of claim 13 , further comprising heating the substrate after forming the buffer layer to a temperature between 300 degrees C. and 800 degrees C.
21 . The method of claim 13 , further comprising the steps of:
depositing a semiconductor window layer adjacent to the buffer layer;
depositing a semiconductor absorber layer adjacent to the semiconductor window layer; and
forming a back contact adjacent to the semiconductor absorber layer.
22 . The method of claim 13 , wherein the metal oxide is selected from the group consisting of tin oxide, zinc oxide, and zinc tin oxide, and the anion comprises a halide ion.
23 . The method of claim 22 , wherein the halide ion is selected from the group consisting of a fluoride ion and a chloride ion.
24 . A photovoltaic device comprising:
a substrate;
a barrier layer adjacent to the substrate;
a transparent conductive oxide layer adjacent to the barrier layer;
a buffer layer adjacent to the transparent conductive oxide layer, wherein the buffer layer comprises a metal oxide doped with a Group V element;
a semiconductor window layer adjacent to the buffer layer;
a semiconductor absorber layer adjacent to the semiconductor window layer; and
a back contact adjacent to the semiconductor absorber layer.
25 . The photovoltaic device of claim 24 , wherein the semiconductor window layer comprises cadmium sulfide and the semiconductor absorber layer comprises cadmium telluride.
26 . The photovoltaic device of claim 24 , wherein the semiconductor absorber layer comprises amorphous silicon.
27 . A sputter target comprising:
a sputter material containing a metal and a dopant, wherein the metal is selected from the group consisting of tin and zinc and the dopant is selected from the group consisting of arsenic, antimony, vanadium, niobium, and tantalum; and
a backing tube, wherein the sputter material is connected to the backing tube to form a sputter target.
28 . The sputter target of claim 27 comprising a dopant concentration in the sputter material is between 10 15 and 10 20 atoms/cm 3 .
29 . The sputter target of claim 27 , further comprising a bonding layer bonding the sputter material and the backing tube.
30 . The sputter target of claim 29 , wherein the backing tube comprises stainless steel.
31 . 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 a metal and a dopant, wherein the metal is selected from the group consisting of tin and zinc and the dopant is selected from the group consisting of arsenic, antimony, vanadium, niobium, and tantalum; and
attaching the sputter material to a backing tube to form a sputter target.