According to various implementations of the invention, a vertical Josephson Junction device may be realized using molecular beam epitaxy (MBE) growth of YBCO and PBCO epitaxial layers in an a-axis crystal orientation. Various implementations of the invention provide improved vertical JJ devices using SiC or LSGO substrates; GaN, AlN, or MgO buffer layers; YBCO or LSGO template layers; YBCO conductive layers and various combinations of barrier layers that include PBCO, NBCO, and DBCO. Such JJ devices are simple to fabricate with wet and dry etching, and allow for superior current flow across the barrier layers.

A high-temperature superconducting qubit implements a quantum mechanical two-level system. The high-temperature superconducting qubit comprises a first superconductor, a second superconductor, and an overlap region. The first superconductor comprises a first high-temperature superconductor material. The second superconductor comprises a second high-temperature superconductor material. In the overlap region, at least a first section of the first surface and at least a second section of the second surface overlap, the first section and the second section are arranged in parallel at a distance corresponding to a predefined distance, and the first orientation and the second orientation are arranged with an angle corresponding to a predefined angle. The high-temperature superconducting qubit comprises a Josephson junction between the first high-temperature superconductor material and the second high-temperature superconductor material. The Josephson junction provides the quantum mechanical two-level system of the high-temperature superconducting qubit.

An antenna comprising; a substrate; a continuous film of yttrium barium copper oxide (YBCO) disposed on the substrate having first and second regions, wherein the first region has a first oxygen doping level and wherein the second region has a second oxygen doping level that is different from the first oxygen doping level; a nano-scale conductive structure, shaped to resonate at a terahertz (THz) frequency, disposed on a boundary between the first and second regions; and a conductive path electrically connected to the first and second regions and to the conductive structure such that induced current in the structure due to incoming THz radiation heats the boundary thereby creating a thermal gradient, which results in the generation of Seebeck effect voltage.

An antenna comprising; a substrate; a continuous film of yttrium barium copper oxide (YBCO) disposed on the substrate having first and second regions, wherein the first region has a first oxygen doping level and wherein the second region has a second oxygen doping level that is different from the first oxygen doping level; a nano-scale conductive structure, shaped to resonate at a terahertz (THz) frequency, disposed on a boundary between the first and second regions; and a conductive path electrically connected to the first and second regions and to the conductive structure such that induced current in the structure due to incoming THz radiation heats the boundary thereby creating a thermal gradient, which results in the generation of Seebeck effect voltage.

A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8° K on the buffer layer, and a capping layer, respectively.

According to various implementations of the invention, high quality a-axis XBCO may be grown with low surface roughness. According to various implementations of the invention, low surface roughness may be obtained by: 1) adequate substrate preparation; 2) calibration of flux rates for constituent atoms; and/or 3) appropriate control of temperature during crystal growth. According to various implementions of the invention, a wafer comprises a smoothing layer of c-axis XBCO; a first conducting layer of a-axis XBCO formed on the smoothing layer; an insulating layer formed on the first conducting layer; and a second conducting layer of a-axis XBCO formed on the insulating layer, where, for a same surface roughness, a thickness of the smoothing layer and the first conducting layer combined is greater than a thickness of the first conducting layer without the smoothing layer. According to various implementations of the invention, a Josephson Junction is etched out of the XBCO/insulating layer/XBCO trilayer by: ion mill etching the top XBCO layer and some of the insulating layer to intentionally leave some of the insulating layer on the bottom XBCO layer; and/or ion mill etching at least the insulating layer at an off angle to reduce or minimize ion damage to the bottom XBCO layer otherwise introduced by the ion mill.

According to various implementations of the invention, high quality a-axis XBCO may be grown with low surface roughness. According to various implementations of the invention, low surface roughness may be obtained by: 1) adequate substrate preparation; 2) calibration of flux rates for constituent atoms; and/or 3) appropriate control of temperature during crystal growth. According to various implementations of the invention, a wafer comprises a smoothing layer of c-axis XBCO; a first conducting layer of a-axis XBCO formed on the smoothing layer; an insulating layer formed on the first conducting layer; and a second conducting layer of a-axis XBCO formed on the insulating layer, where, for a same surface roughness, a thickness of the smoothing layer and the first conducting layer combined is greater than a thickness of the first conducting layer without the smoothing layer.

According to various implementations of the invention, a vertical Josephson Junction device may be realized using molecular beam epitaxy (MBE) growth of YBCO and PBCO epitaxial layers in an a-axis crystal orientation. Various implementations of the invention provide improved vertical JJ devices using SiC or LSGO substrates; GaN, AlN, or MgO buffer layers; YBCO or LSGO template layers; YBCO conductive layers and various combinations of barrier layers that include PBCO, NBCO, and DBCO. Such JJ devices are simple to fabricate with wet and dry etching, and allow for superior current flow across the barrier layers.

The present disclosure further relates to nanostructures, in particular hybrid nanostructures with patterned growth of various layers for use in nanoscale electronic devices, such as hybrid semiconductor nanostructures with patterned growth and/or deposition of superconducting material for use in quantum devices. The presently disclosed method can be utilized for in-situ manufacturing of nanoscale electronic devices that have not been contaminated by ex-situ processes. One embodiment relates to a method for manufacturing a substrate for growth of crystalline nanostructures, the method comprising the steps of: depositing one or more layers of a crystal growth compatible dielectric material, such as silicon oxide, in a predefined pattern on the surface of a crystal growth compatible substrate to create a predefined etch pattern of said crystal growth compatible material, and selectively etching the substrate surface around said etch pattern to provide at least one under-etched platform which is vertically raised from the etched substrate surface.

A physical vapor deposition system includes a chamber, three target supports to targets, a movable shield positioned having an opening therethrough, a workpiece support to hold a workpiece in the chamber, a gas supply to deliver nitrogen gas and an inert gas to the chamber, a power source, and a controller. The controller is configured to move the shield to position the opening adjacent each target in turn, and at each target cause the power source to apply power sufficient to ignite a plasma in the chamber to cause deposition of a buffer layer, a device layer of a first material that is a metal nitride suitable for use as a superconductor at temperatures above 8° K on the buffer layer, and a capping layer, respectively.