Formation of a correlated electron material (CEM)
Subject matter disclosed herein may relate to fabrication of a correlated electron material (CEM) such as in a CEM device capable of switching between and/or among impedance states. In particular embodiments, a CEM may be formed from one or more transition metal oxides (TMOs), one or more post transition metal oxides (PTMOs) or one or more post transition metal chalcogenides (PTMCs), or a combination thereof.
1. A method comprising:
applying a dopant to a material comprising substantially a metal oxide or a metal chalcogenide, or a combination thereof, to form a correlated electron material (CEM);
wherein:
the dopant to provide a ligand to substantially bond with metal ions of the metal oxide or the metal chalcogenide, or a combination thereof; and
wherein p-orbitals of oxygen atoms of the metal oxide, or p-orbitals of chalcogenide atoms of the metal chalcogenide, or a combination thereof, to form a hybridized orbital with s-p orbitals of metal ions in a valence band and a conduction band.
2. The method of claim 1 , wherein application of the dopant is to reduce a bandgap in the CEM.
3. The method of claim 1 , wherein the dopant comprises carbon and/or carbon monoxide, and the metal oxide comprises Bi 2 O 3 , and wherein the CEM comprises CO maintained in a lattice comprising Bi 2 O 3 .
4. The method of claim 1 , wherein the dopant comprises carbon in a solid state, and wherein the metal oxide comprises Bi 2 O 3 , and wherein application of the dopant to the metal oxide comprises:
a reduction of Bi 2 O 3 to form a carbon monoxide gas and bismuth solid; and
an oxidation of the bismuth by carbon dioxide to form Bi 2 O 3 and additional carbon monoxide.
5. The method of claim 4 , and further comprising varying amounts of carbon and/or carbon monoxide applied in the dopant so as to control a removal of O vacancies in the CEM and to maintain an amount of carbon monoxide in a lattice comprising Bi 2 O 3 .
6. The method of claim 1 , wherein the metal oxide comprises an oxide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
7. The method of claim 1 , wherein the metal chalcogenide comprises a chalcogenide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
8. The method of claim 1 , wherein the metal chalcogenide comprises a metal chalcogenide of S, Se, or Te, or any combination thereof.
9. A method comprising:
applying a dopant to a material comprising substantially a metal oxide or a metal chalcogenide, or a combination thereof, to form a correlated electron material (CEM), the dopant providing a ligand to substantially bond with metal ions of the metal oxide or the metal chalcogenide, or a combination thereof, wherein applying the dopant further comprises:
applying an extrinsic ligand to the metal oxide or the metal chalcogenide, or the combination thereof; and
varying an applied amount of the extrinsic ligand to impart an atomic concentration of the extrinsic ligand in the correlated electron material to achieve a predefined bandgap between conduction and valence bands of the correlated electron material or achieve a predefined electronegativity in the correlated electron material, or a combination thereof.
10. The method of claim 9 , wherein the extrinsic ligand forms hybridized bonds with s- and p-orbitals of the metal ions to at least in part displace oxygen or a chalcogen in hybridized bonds with s- and p-orbitals of the metal ions.
11. The method of claim 10 , wherein the predefined bandgap between the conduction and valence bands or predefined electronegativity in the correlated electron material, or a combination thereof, are achieved responsive at least in part to a degree of displacement of oxygen or a chalcogen in hybridized bonds with s- and p-orbitals of the metal ions by the extrinsic ligand.
12. The method of claim 9 , wherein the metal oxide comprises an oxide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
13. The method of claim 9 , wherein the metal chalcogenide comprises a chalcogenide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
14. The method of claim 9 , wherein the metal chalcogenide comprises a metal chalcogenide of S, Se, or Te, or any combination thereof.
15. A method comprising:
forming one or more layers of a bulk material between first and second metal layers, the one or more layers of the bulk material comprising substantially a metal oxide or a metal chalcogenide, or a combination thereof, the bulk material further comprising a ligand to bond with metal ions of the metal oxide or the metal chalcogenide, or the combination thereof, to impart a reversible back donation property, wherein p orbitals of oxygen atoms of the metal oxide or p- orbitals of chalcogenide atoms of the metal chalcogenide, or a combination thereof, form a hybridized orbital with s-p orbitals of metal ions in a valence band and a conduction band.
16. The method of claim 15 , wherein the bulk material comprises a correlated electron material (CEM), and wherein the ligand is to reduce a bandgap in the CEM.
17. The method of claim 15 , wherein the ligand comprises carbon and/or carbon monoxide, and the metal oxide comprises Bi 2 O 3 , and wherein the bulk material comprises CO maintained in a lattice comprising Bi 2 O 3 .
18. The method of claim 15 , wherein the metal oxide comprises an oxide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
19. The method of claim 15 , wherein the metal chalcogenide comprises a chalcogenide of Bi, Pb, Zn, Cd, In, Sn, Sb, Hg, TI, Ga or Ge, or any combination thereof.
20. The method of claim 15 , wherein the metal chalcogenide comprises a metal chalcogenide of S, Se, or Te, or any combination thereof.