ENHANCING EFFICIENCY IN SOLAR CELLS BY ADJUSTING DEPOSITION POWER
Methods for forming a photovoltaic device include adjusting a deposition power for depositing a buffer layer including germanium on a transparent electrode. The deposition power is configured to improve device efficiency. A p-type layer is formed on the buffer layer. An intrinsic layer and an n-type layer are formed over the p-type layer.
1 . A method for forming a photovoltaic device, comprising:
adjusting a deposition power for depositing a buffer layer including germanium on a transparent electrode, the deposition power being configured to improve device efficiency;
forming a p-type layer on the buffer layer; and
forming an intrinsic layer and an n-type layer over the p-type layer.
2 . The method as recited in claim 1 , wherein depositing the buffer layer includes depositing at least one of a hydrogenated amorphous silicon germanium alloy, a hydrogenated microcrystalline silicon-germanium alloy, a hydrogenated amorphous germanium or a hydrogenated microcrystalline germanium.
3 . The method as recited in claim 1 , wherein the deposition power is increased to increase fill factor.
4 . The method as recited in claim 1 , wherein the buffer layer is formed by a GeH 4 plasma enhanced deposition.
5 . The method as recited in claim 1 , wherein the p-type layer, the intrinsic layer and the n-type layer are formed at a temperature of about 250 degrees Celsius.
6 . The method as recited in claim 1 , wherein the buffer layer aligns band gap energies between the transparent electrode and the p-type layer.
7 . The method as recited in claim 1 , further comprising adjusting a deposition power for the p-type layer to improve device efficiency.
8 . The method as recited in claim 1 , wherein the p-type layer includes a form of silicon.
9 . The method as recited in claim 8 , wherein the p-type layer includes at least one of amorphous silicon, amorphous silicon carbide, hydrogenated amorphous silicon, or hydrogenated amorphous silicon carbide.
10 . A method for forming a photovoltaic device, comprising:
forming a transparent electrode on a transparent substrate, the transparent electrode having a first Fermi level;
adjusting a deposition power for depositing a buffer layer including germanium on the transparent electrode, the deposition power being configured to improve device efficiency, the buffer layer having a Fermi level aligned with the first Fermi level;
depositing a p-type layer on the buffer layer, the p-type layer having a conduction band level aligned with a conduction band level of the buffer layer;
forming an intrinsic layer on the p-type layer; and
forming an n-type layer on the intrinsic layer.
11 . The method as recited in claim 10 , wherein depositing the buffer layer includes depositing at least one of a hydrogenated amorphous silicon germanium alloy, a hydrogenated microcrystalline silicon-germanium alloy, a hydrogenated amorphous germanium or a hydrogenated microcrystalline germanium.
12 . The method as recited in claim 10 , wherein the deposition power is increased to increase fill factor.
13 . The method as recited in claim 10 , wherein the buffer layer is formed by a GeH 4 plasma enhanced deposition.
14 . The method as recited in claim 10 , wherein the p-type layer, the intrinsic layer and the n-type layer are formed at a temperature of about 250 degrees Celsius.
15 . The method as recited in claim 10 , further comprising adjusting a deposition power for the p-type layer to improve device efficiency.
16 . The method as recited in claim 10 , wherein the p-type layer includes a form of silicon.
17 . The method as recited in claim 16 , wherein the p-type layer includes at least one of amorphous silicon, amorphous silicon carbide, hydrogenated amorphous silicon, or hydrogenated amorphous silicon carbide.
18 . A method for forming a photovoltaic device, comprising:
forming a transparent conductive oxide on a transparent substrate;
adjusting a first deposition power for depositing a buffer layer including germanium on the transparent electrode, the first deposition power being configured to improve device efficiency;
adjusting a second deposition power for depositing a p-type amorphous layer on the buffer layer such that the second deposition power is configured to improve device efficiency;
forming an amorphous silicon intrinsic layer on the p-type layer;
forming an amorphous silicon n-type layer on the intrinsic layer; and
forming a back reflector on the n-type layer.
19 . The method as recited in claim 18 , wherein depositing the buffer layer includes depositing at least one of a hydrogenated amorphous silicon germanium alloy, a hydrogenated microcrystalline silicon-germanium alloy, a hydrogenated amorphous germanium or a hydrogenated microcrystalline germanium.
20 . The method as recited in claim 18 , wherein the p-type layer includes at least one of amorphous silicon, amorphous silicon carbide, hydrogenated amorphous silicon, or hydrogenated amorphous silicon carbide.
21 . A method for forming a photovoltaic device, comprising:
forming a transparent electrode on a transparent substrate, the transparent electrode having a first Fermi level;
depositing a buffer layer including germanium on the transparent electrode, the buffer layer having a Fermi level substantially aligned with the first Fermi level;
adjusting a deposition power for forming a p-type layer on the buffer layer, the deposition power being configured to improve device efficiency, the p-type layer having a conduction band level aligned with a conduction band level of the buffer layer;
forming an intrinsic layer on the p-type layer; and
forming an n-type layer on the intrinsic layer.
22 . The method as recited in claim 21 , wherein the buffer layer aligns band gap energies between the transparent electrode and the p-type layer.