Interlayer design for epitaxial growth of semiconductor layers
An interlayer structure that, in one implementation, includes a combination of an amorphous or nano-crystalline seed-layer, and one or more metallic layers, deposited on the seed layer, with the fcc, hcp or bcc crystal structure is used to epitaxially orient a semiconductor layer on top of non-single-crystal substrates. In some implementations, this interlayer structure is used to establish epitaxial growth of multiple semiconductor layers, combinations of semiconductor and oxide layers, combinations of semiconductor and metal layers and combination of semiconductor, oxide and metal layers. This interlayer structure can also be used for epitaxial growth of p-type and n-type semiconductors in photovoltaic cells.
1. A photovoltaic cell, comprising
a non-textured substrate;
a non-magnetic amorphous or nanocrystalline seed layer disposed over the substrate, the
seed layer being a metallic material;
an underlayer comprising one or more metallic sub-layers deposited over the seed layer,
wherein the underlayer layer promotes growth in a first growth direction of a majority of grains of one or more overlying semiconductor layers;
a first semiconductor layer comprising an electron conducting material;
a second semiconductor layer comprising a hole conducting material; and
a transparent conductive layer.
2. The photovoltaic cell of claim 1 wherein the first semiconductor layer comprises two or more semiconductor sub-layers each comprising a hole conducting material.
3. The photovoltaic cell of claim 1 wherein the second semiconductor layer comprises two or more semiconductor sub-layers each comprising an electron conducting material.
4. The photovoltaic cell of claim 1 wherein the first semiconductor layer comprises two or more semiconductor sub-layers each comprising a hole conducting material and the second semiconductor layer comprises two or more semiconductor sub-layers each comprising an electron conducting material.
5. A photovoltaic cell, comprising
a non-textured substrate;
a non-magnetic amorphous or nanocrystalline seed layer disposed over the substrate, the seed layer being a metallic material;
an fcc underlayer with <111>growth directions formed over the seed layer;
a bcc underlayer with <110>growth directions formed over the fcc underlayer, wherein the bcc underlayer promotes growth in a first growth direction of a majority of grains of one or more overlying semiconductor layers;
a first semiconductor layer comprising an electron conducting material;
a second semiconductor layer comprising a hole conducting material; and
a transparent conductive layer.
6. The photovoltaic cell of claim 5 wherein the first semiconductor layer is formed over the second semiconductor layer, and wherein the second semiconductor layer is formed over the bcc underlayer.
7. The photovoltaic cell of claim 5 wherein the second semiconductor layer is formed over the first semiconductor layer.
8. The photovoltaic cell of claim 5 wherein at least one of the first and second semiconductor layers comprises one or more semiconductor and oxide layers comprising an oxide and a semiconductor, wherein the oxide is dispersed at grain boundaries of the semiconductor.
9. The photovoltaic cell of claim 1 wherein the first semiconductor layer or the second semiconductor layer is deposited onto the underlayer layer.
10. The photovoltaic cell of claim 1 wherein the underlayer comprises at least one metallic material having hcp or fcc or bcc lattice structure with a <0001>or <111>or <110>growth directions.
11. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has an hcp lattice structure with <0001>growth directions and a second metallic material of the underlayer has an fcc lattice structure with <111>growth directions.
12. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has an fcc lattice structure with <111>growth directions and a second metallic material of the underlayer has a bcc lattice structure with <110>growth directions.
13. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has an hcp lattice structure with <0001>growth directions and a second metallic material of the underlayer has a bcc lattice structure with <110>growth directions.
14. The photovoltaic cell of claim 1 wherein the underlayer comprises at least three metallic materials, wherein a first metallic material of the underlayer has a fcc lattice structure with <111>growth directions, a second metallic material of the underlayer has a hcp lattice structure with <0001>growth directions, and a third metallic material of the underlayer has a bcc lattice structure with <110>growth directions.
15. The photovoltaic cell of claim 1 wherein the seed layer comprises Si 3 N 4 .
16. The photovoltaic cell of claim 1 wherein the seed layer comprises at least one metallic nanocrystalline or amorphous layer.
17. The photovoltaic cell of claim 16 wherein at least one seed layer comprises:
at least one element from the group consisting of V, Cr, Mn, Fe, Co, and Ni; and
at least one element from the group consisting of B, C, Al, Si, P, Sc, Ti, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Te, Hf, Ta, W, Re, Ir, Pt, and Au.
18. The photovoltaic cell of claim 16 wherein at least one seed layer comprises:
10 to 96 at. % of least one element from the group consisting of V, Cr, Mn, Fe, Co, and Ni; and
4 to 50 at. % of least one element from the group consisting of B, C, P, Si, Ti, Ge, Zr, Mo, Hf, Ta, and W.
19. The photovoltaic cell of claim 16 wherein at least one seed layer comprises:
10 to 90 at. % of least one element from the group consisting of V, Cr, Mn, Fe, Co, and Ni;
4 to 50 at. % of least one element from the group consisting of B, C, P, Si, Ge, Zr, Mo, Hf, Ta, and W; and
at least one element from the group consisting of Al, Sc, Ti, Cu, Zn, Ga, Sr, Y, Ru, Rh, Pd, Ag, In, Te, Sn, Re, Ir, Pt, and Au.
20. The photovoltaic cell of claim 16 wherein at least one seed layer comprises at least one element selected from the group consisting of B, P, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Te, Hf, Ta, W, Re, Ir, Pt, and Au.
21. The photovoltaic cell of claim 1 wherein the underlayer comprises at least one metallic material having a hcp or fcc or bcc lattice structure.
22. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the hcp lattice structure and wherein the underlayer comprises at least one element from the group consisting of Sc, Ti, Co, Zn, Y, Zr, Ru, Hf, and Re.
23. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the hcp lattice structure and wherein the underlayer comprises:
at least one element from the group consisting of Sc, Ti, Co, Zn, Y, Zr, Ru, Hf, and Re; and
at least one element from the group consisting of B, C, N, 0 , Na, Si, S, P, K, Al, V, Cr, Mn, Fe, Ni, Cu, Ga, Ge, Se, Nb, Mo, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ta, W, Ir, Pt, Au, and Bi.
24. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the fcc lattice structure and wherein the underlayer comprises at least one element from the group consisting of Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au, and Pb.
25. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the fcc lattice structure and wherein the underlayer comprises:
at least one element from the group consisting of Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au, and Pb; and
at least one element from the group consisting of B, C, N, 0 , Na, Si, S, P, K, Sc, Ti, V, Cr, Mn, Fe, Co, Zn, Ga, Ge, Se, Y, Zr, Nb, Mo, Ru, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, and Bi.
26. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the bcc lattice structure and wherein the underlayer comprises at least one element from the group consisting of V, Cr, Fe, Nb, Mo, Ta, W.
27. The photovoltaic cell of claim 21 wherein the metallic material of the underlayer has the bcc lattice structure and wherein the underlayer comprises:
at least one element from the group consisting of V, Cr, Fe, Nb, Mo, Ta, and W; and
at least one element from the group consisting of B, C, N, 0 , Na, Si, S, P, K, Sc, Ti, Mn, Co, Ni, Cu, Zn, Ga, Ge, Se, Y, Zr, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Hf, Re, Ir, Pt, Au, and Bi.
28. The photovoltaic cell of claim 1 wherein the underlayer comprises at least one metallic material having an hcp lattice structure with <0001>growth directions or an fcc lattice structure with <111>growth directions, or a bcc lattice structure with <110>growth directions.
29. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has a hcp lattice structure with <0001>growth directions and a second metallic material of the underlayer has a fcc lattice structure with <111>growth directions.
30. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has a fcc lattice structure with <111>growth directions and a second metallic material of the at least two metallic materials has a bcc lattice structure with <110>growth directions.
31. The photovoltaic cell of claim 1 wherein the underlayer comprises at least two metallic materials, wherein a first metallic material of the underlayer has a hcp lattice structure with <0001>growth directions and a second metallic material of the at least two metallic materials has a bcc lattice structure with <110>growth directions.
32. The photovoltaic cell of claim 1 , wherein the underlayer promotes substantially epitaxial growth of one or more overlying semiconductor layers.
33. The photovoltaic cell of claim 1 , wherein the underlayer promotes textured growth of one or more overlying semiconductor layers.
34. The photovoltaic cell of claim 1 , wherein the seed layer promotes growth in a second growth direction of a majority of grains of the overlying underlayer.