Abstract: Memristors are provided, which, in embodiments, comprise a bottom electrode; a top electrode in electrical communication with the bottom electrode, wherein one or both of the bottom and top electrodes is a Schottky electrode; and a dielectric stack between the bottom and top electrodes, the dielectric stack forming a top interface with a bottom surface of the top electrode and a bottom interface with a top surface of the bottom electrode, the dielectric stack comprising a plurality of atomic layer deposition (ALD)-grown atomic sublayers, the plurality comprising an ALD-grown atomic sublayer of a first metal oxide and an ALD-grown atomic sublayer of a second metal oxide. The second metal oxide is different from the first metal oxide and has a greater concentration of oxygen vacancies (VO) than the first metal oxide. The dielectric stack has a thickness of no more than about 5 nm.

Abstract: A method of making a plasmonic metal/graphene heterostructure comprises heating an organometallic complex precursor comprising a metal at a first temperature T1 for a first period of time t1 to deposit a layer of the metal on a surface of a heated substrate, the heated substrate in fluid communication with the precursor; and heating, in situ, the precursor at a second temperature T2 for a second period of time t2 to simultaneously form on the layer of the metal, a monolayer of graphene and a plurality of carbon-encapsulated metal nanostructures comprising the metal, thereby providing the plasmonic metal/graphene heterostructure. The heated substrate is characterized by a third temperature T3. The plasmonic metal/graphene heterostructures, devices incorporating the heterostructures, and methods of using the heterostructures are also provided.

Abstract: Superconducting nanocomposites are provided. One such nanocomposite comprises a high temperature superconductor (HTS); a plurality of artificial pinning centers (APCs) in the form of one-dimensional (1D) nanorods distributed throughout the HTS and oriented parallel to a c-axis of the HTS, each APC composed of a non-superconducting material and surrounded by the HTS, thereby forming an APC-HTS interface; and one or more repair regions composed of a repair material comprising a cation A, wherein a portion of the cation A of the repair material has diffused out of the one or more repair regions and into the HTS.

Abstract: Plasmonic substrates are provided which may be used in a variety of optoelectronic devices, e.g., biosensors and photodetectors. The plasmonic substrate may comprise a layer of graphene and a plurality of discrete, individual transition metal chalcogenide nanodomes distributed on a surface of the layer of graphene, each nanodome surrounded by bare graphene. Methods for making and using the plasmonic substrates are also provided.

Abstract: A method of making a plasmonic metal/graphene heterostructure comprises heating an organometallic complex precursor comprising a metal at a first temperature T1 for a first period of time t1 to deposit a layer of the metal on a surface of a heated substrate, the heated substrate in fluid communication with the precursor; and heating, in situ, the precursor at a second temperature T2 for a second period of time t2 to simultaneously form on the layer of the metal, a monolayer of graphene and a plurality of carbon-encapsulated metal nanostructures comprising the metal, thereby providing the plasmonic metal/graphene heterostructure. The heated substrate is characterized by a third temperature T3. The plasmonic metal/graphene heterostructures, devices incorporating the heterostructures, and methods of using the heterostructures are also provided.

Abstract: Methods for forming tunnel barrier layers are provided, including a method comprising exposing a surface of a material, the surface free of oxygen, to an initial water pulse for a pulse time and at a pulse temperature, the pulse time and pulse temperature selected to maximize hydroxylation of the surface; and exposing the hydroxylated surface to alternating, separated pulses of precursors under conditions to induce reactions between the hydroxylated surface and the precursors to form a tunnel barrier layer on the surface of the material via atomic layer deposition (ALD), the tunnel barrier layer having an average thickness of no more than 1 nm and being formed without an intervening interfacial layer between the tunnel barrier layer and the surface of the material.

Abstract: An optoelectronic device comprises a nanocomposite comprising a carbon nanostructure having a surface and a biomolecule adsorbed on the surface and forming a heterojunction at the interface of the carbon nanostructure and the biomolecule, the carbon nanostructure and the biomolecule each characterized by respective conduction band edges and valence band edges. The device further comprises first and second electrodes in electrical communication with the nanocomposite. The conduction band edge offset, the valence band edge offset, or both, across the heterojunction is greater in energy than the binding energy of an exciton generated in the carbon nanostructure or the biomolecule upon the absorption of light such that the exciton dissociates at the heterojunction to an electron, which is injected into one of the carbon nanostructure and the biomolecule, and a hole, which is injected into the other of the carbon nanostructure and the biomolecule.

Abstract: Methods for forming tunnel barrier layers are provided, including a method comprising exposing a surface of a material, the surface free of oxygen, to an initial water pulse for a pulse time and at a pulse temperature, the pulse time and pulse temperature selected to maximize hydroxylation of the surface; and exposing the hydroxylated surface to alternating, separated pulses of precursors under conditions to induce reactions between the hydroxylated surface and the precursors to form a tunnel barrier layer on the surface of the material via atomic layer deposition (ALD), the tunnel barrier layer having an average thickness of no more than 1 nm and being formed without an intervening interfacial layer between the tunnel barrier layer and the surface of the material.

Abstract: An apparatus for in situ fabrication of multilayer heterostructures is provided comprising a first vacuum chamber adapted for atomic layer deposition and comprising a first stage docking assembly configured to dock a detachable stage configured to support a substrate; a second vacuum chamber adapted for ultra-high vacuum physical or chemical vapor deposition and comprising a second stage docking assembly configured to dock the detachable stage; a load lock vacuum chamber between the first and second vacuum chambers and comprising a third stage docking assembly configured to dock the detachable stage, the load lock vacuum chamber coupled to the first vacuum chamber via a first shared valve and coupled to the second vacuum chamber via a second shared valve; and a substrate transport vacuum chamber comprising a substrate transfer device, the substrate transfer device configured to detachably couple to the detachable stage and to transfer the substrate supported by the detachable stage in situ between the first v

Abstract: An optoelectronic device comprises a nanocomposite comprising a carbon nanostructure having a surface and a bio molecule adsorbed on the surface and forming a heterojunction at the interface of the carbon nanostructure and the biomolecule, the carbon nanostructure and the biomolecule each characterized by respective conduction band edges and valence band edges. The device further comprises first and second electrodes in electrical communication with the nanocomposite. The conduction band edge offset, the valence band edge offset, or both, across the heterojunction is greater in energy than the binding energy of an exciton generated in the carbon nanostructure or the biomolecule upon the absorption of light such that the exciton dissociates at the heterojunction to an electron, which is injected into one of the carbon nanostructure and the biomolecule, and a hole, which is injected into the other of the carbon nanostructure and the biomolecule.

Abstract: Disclosed are ultrathin layers of group II-VI semiconductors, group II-VI semiconductor superlattice structures, photovoltaic devices incorporating the layers and superlattice structures and related methods. The superlattice structures comprise an ultrathin layer of a first group II-VI semiconductor alternating with an ultrathin layer of at least one additional semiconductor, e.g., a second group II-VI semiconductor, or a group IV semiconductor, or a group III-V semiconductor.

Abstract: A biosensor system comprises a capillary substrate, conductive electrode, and a plurality of nanoparticles having an enzyme deposited thereon formed in a cavity at one end of the capillary substrate. The substrate may have an optional reinforcing layer (which may be conductive or non-conductive) and optional insulating layer thereon. A cannula having an optional conductive layer, insulating layer, and reference electrode may also form part of the system.

Abstract: An apparatus for in situ fabrication of multilayer heterostructures is provided comprising a first vacuum chamber adapted for atomic layer deposition and comprising a first stage docking assembly configured to dock a detachable stage configured to support a substrate; a second vacuum chamber adapted for ultra-high vacuum physical or chemical vapor deposition and comprising a second stage docking assembly configured to dock the detachable stage; a load lock vacuum chamber between the first and second vacuum chambers and comprising a third stage docking assembly configured to dock the detachable stage, the load lock vacuum chamber coupled to the first vacuum chamber via a first shared valve and coupled to the second vacuum chamber via a second shared valve; and a substrate transport vacuum chamber comprising a substrate transfer device, the substrate transfer device configured to detachably couple to the detachable stage and to transfer the substrate supported by the detachable stage in situ between the first v

Abstract: Disclosed are ultrathin layers of group II-VI semiconductors, group II-VI semiconductor superlattice structures, photovoltaic devices incorporating the layers and superlattice structures and related methods. The superlattice structures comprise an ultrathin layer of a first group II-VI semiconductor alternating with an ultrathin layer of at least one additional semiconductor, e.g., a second group II-VI semiconductor, or a group IV semiconductor, or a group III-V semiconductor.

Abstract: A biosensor system comprises a capillary substrate, conductive electrode, and a plurality of nanoparticles having an enzyme deposited thereon formed in a cavity at one end of the capillary substrate. The substrate may have an optional reinforcing layer (which may be conductive or non-conductive) and optional insulating layer thereon. A cannula having an optional conductive layer, insulating layer, and reference electrode may also form part of the system.

Abstract: Planarizing High Temperature Superconductor (HTS) surfaces, especially HTS thin film surfaces is crucial for HTS thin film device processing. Disclosed is a method of surface planarization for HTS film. The method includes first smoothing the HTS surface by Gas Cluster Ion Beam bombardment, followed by annealing in partial pressure of oxygen to regrow the damaged surface layer. A rough HTS surface can be planarized down to a smoothness with a standard deviation of one nanometer or better.

Abstract: Planarizing High Temperature Superconductor (HTS) surfaces, especially HTS thin film surfaces is crucial for HTS thin film device processing. Disclosed is a method of surface planarization for HTS film. The method includes first smoothing the HTS surface by Gas Cluster Ion Beam bombardment, followed by annealing in partial pressure of oxygen to regrow the damaged surface layer. A rough HTS surface can be planarized down to a smoothness with a standard deviation of one nanometer or better.

Abstract: A Hg-based superconducting cuprate film on a substrate is disclosed, which comprises a compound having the formula Hg.sub.1-x M.sub.x Ba.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.y, M is a metal cation, x ranges from 0 to 1, n is an integer greater than 0, and y is an oxygen sufficiency factor having a value less than about 10.

Abstract: Alkaline-doped superconductors of the formulaX M.sub.2 Ca.sub.2 Cu.sub.3 O.sub.8+.alpha.are provided where X is selected from the group consisting of TI, Pb, Mo, Hg and mixtures thereof, M is selected from the group consisting of Ba, Sr and mixtures thereof, and a ranges from zero to about 0.2, and being doped with a dopant selected from the group consisting of Na and Li up to a level of up to about 12% molar ratio, based upon the amount of the element X taken as 100%. The superconductors of the invention exhibit extremely high T.sub.c onset and T.sub.cO values and have high J.sub.c properties as well. The superconductors can be fabricated at relatively low annealing temperatures (750.degree.-820.degree. C.) making them suitable for use as thin films with a variety of conventional substrates.