Abstract: The present disclosure relates to a method of manufacturing a nanowire structure. According to an exemplary process, a substrate is firstly provided. An intact buffer region is formed over the substrate, and a sacrificial top portion of the intact buffer region is eliminated to provide a buffer layer with a planarized top surface. Herein, the planarized top surface has a vertical roughness below 10 ?. Next, a patterned mask with an opening is formed over the buffer layer, such that a portion of the planarized top surface of the buffer layer is exposed. A nanowire is formed over the exposed portion of the planarized top surface of the buffer layer through the opening of the patterned mask. The buffer layer is configured to have a lattice constant that provides a transition between the lattice constant of the substrate and the lattice constant of the nanowire.

Abstract: Methods of forming semiconductor-superconductor hybrid devices with a horizontally-confined channel are described. An example method includes forming a first isolated semiconductor heterostructure and a second isolated semiconductor heterostructure. The method further includes forming a left gate adjacent to a first side of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure. The method further includes forming a right gate adjacent to a second side, opposite to the first side, of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure, where a top surface of each of the left gate and the right gate is offset vertically from a selected surface of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure by a predetermined offset amount.

Abstract: Methods of forming semiconductor-superconductor hybrid devices with a horizontally-confined channel are described. An example method includes forming a first isolated semiconductor heterostructure and a second isolated semiconductor heterostructure. The method further includes forming a left gate adjacent to a first side of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure. The method further includes forming a right gate adjacent to a second side, opposite to the first side, of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure, where a top surface of each of the left gate and the right gate is offset vertically from a selected surface of each of the first isolated semiconductor heterostructure and the second isolated semiconductor heterostructure by a predetermined offset amount.

Abstract: A nanowire structure includes a substrate, a graded planar buffer layer, a patterned mask, and a nanowire. The graded planar buffer layer is on the substrate. The patterned mask is on the graded planar buffer layer and includes an opening through which the graded planar buffer layer is exposed. The nanowire is on the graded planar buffer layer in the opening of the patterned mask. A lattice constant of the graded planar buffer layer is between a lattice constant of the substrate and a lattice constant of the nanowire. By providing the graded planar buffer layer, lattice mismatch between the nanowire and the substrate can be reduced or eliminated, thereby improving the quality and performance of the nanowire structure.

Abstract: A hybrid heterostructure includes a semiconductor layer comprising indium antimonide, a superconductor layer comprising aluminum, and a screening layer between the semiconductor layer and the superconductor layer, the screening layer comprising indium arsenide. By including a screening layer of indium arsenide between the semiconductor layer of indium antimonide and the superconductor layer of aluminum, a high-performance and durable hybrid heterostructure suitable for use in quantum computing devices is provided.

Abstract: The present disclosure relates to a nanowire structure, which includes a substrate with a substrate body and an ion implantation region, a patterned mask with an opening over the substrate, and a nanowire. Herein, the substrate body is formed of a conducting material, and the ion implantation region that extends from a top surface of the substrate body into the substrate body is electrically insulating. A surface portion of the substrate body is exposed through the opening of the patterned mask, while the ion implantation region is fully covered by the patterned mask. The nanowire is directly formed over the exposed surface portion of the substrate body and is not in contact with the ion implantation region. Furthermore, the nanowire is confined within the ion implantation region, such that the ion implantation region is configured to provide a conductivity barrier of the nanowire in the substrate.

Abstract: The present disclosure relates to a nanowire structure, which includes a substrate with a substrate body and an ion implantation region, a patterned mask with an opening over the substrate, and a nanowire. Herein, the substrate body is formed of a conducting material, and the ion implantation region that extends from a top surface of the substrate body into the substrate body is electrically insulating. A surface portion of the substrate body is exposed through the opening of the patterned mask, while the ion implantation region is fully covered by the patterned mask. The nanowire is directly formed over the exposed surface portion of the substrate body and is not in contact with the ion implantation region. Furthermore, the nanowire is confined within the ion implantation region, such that the ion implantation region is configured to provide a conductivity barrier of the nanowire in the substrate.

Abstract: A method of fabricating a semiconductor-superconductor hybrid device comprises providing a workpiece comprising a semiconductor component, a layer of a first superconductor material on the semiconductor component, and a layer of a second superconductor material on the first superconductor material, the second superconductor material being different from the first superconductor material; etching the layer of the second superconductor material to expose a portion of the first superconductor material; and oxidising the portion of the first superconductor material to form a passivating layer on the semiconductor. The first superconductor provides energy coupling between the semiconductor and the second superconductor, and the passivating layer protects the semiconductor while allowing electrostatic access thereto. Also provided are a hybrid device, and a method of etching.

Abstract: A method of fabricating a semiconductor-superconductor hybrid device comprises providing a workpiece comprising a semiconductor component, a layer of a first superconductor material on the semiconductor component, and a layer of a second superconductor material on the first superconductor material, the second superconductor material being different from the first superconductor material; etching the layer of the second superconductor material to expose a portion of the first superconductor material; and oxidising the portion of the first superconductor material to form a passivating layer on the semiconductor. The first superconductor provides energy coupling between the semiconductor and the second superconductor, and the passivating layer protects the semiconductor while allowing electrostatic access thereto. Also provided are a hybrid device, and a method of etching.

Abstract: A device comprising: a portion of semiconductor; a portion of superconductor arranged to a enable a topological phase having a topological gap to be induced in a region of the semiconductor by proximity effect; and a portion of a non-magnetic material comprising an element with atomic number Z greater than or equal to 26, arranged to increase the topological gap in the topological region of the semiconductor.

Abstract: The present disclosure relates to a nanowire structure, which includes a substrate with a substrate body and an ion implantation region, a patterned mask with an opening over the substrate, and a nanowire. Herein, the substrate body is formed of a conducting material, and the ion implantation region that extends from a top surface of the substrate body into the substrate body is electrically insulating. A surface portion of the substrate body is exposed through the opening of the patterned mask, while the ion implantation region is fully covered by the patterned mask. The nanowire is directly formed over the exposed surface portion of the substrate body and is not in contact with the ion implantation region. Furthermore, the nanowire is confined within the ion implantation region, such that the ion implantation region is configured to provide a conductivity barrier of the nanowire in the substrate.

Abstract: The present disclosure relates to a method of manufacturing a nanowire structure. According to an exemplary process, a substrate is firstly provided. An intact buffer region is formed over the substrate, and a sacrificial top portion of the intact buffer region is eliminated to provide a buffer layer with a planarized top surface. Herein, the planarized top surface has a vertical roughness below 10 ?. Next, a patterned mask with an opening is formed over the buffer layer, such that a portion of the planarized top surface of the buffer layer is exposed. A nanowire is formed over the exposed portion of the planarized top surface of the buffer layer through the opening of the patterned mask. The buffer layer is configured to have a lattice constant that provides a transition between the lattice constant of the substrate and the lattice constant of the nanowire.

Abstract: A quantum well field-effect transistor (QWFET) includes a barrier layer, a quantum well layer, and a spacer layer. The quantum well layer is on the barrier layer. The barrier layer and the spacer layer comprise aluminum indium antimonide that is undoped. The quantum well layer comprises indium antimonide. The spacer layer is on the quantum well layer. The quantum well layer and the spacer layer are between a source contact and a drain contact. A gate contact is on a dielectric layer, which is on the spacer layer. By providing the barrier layer and the spacer layer as undoped layers, a performance of the QWFET may be improved.

Abstract: A semiconductor-superconductor hybrid structure includes a semiconductor layer and a superconductor heterostructure on the semiconductor layer. The superconductor heterostructure includes a first superconductor layer on the semiconductor layer and a second superconductor layer on the first superconductor layer. The first superconductor layer comprises a first superconducting material and the second superconductor layer comprises a second superconducting material that is different from the first superconducting material. By providing the superconductor heterostructure as multiple layers of different superconducting materials, the superconducting and physical properties of the superconductor heterostructure can be improved compared to conventional superconducting homostructures, thereby increasing the performance of the semiconductor-superconductor hybrid structure.

Abstract: A nanowire structure includes a substrate, a graded planar buffer layer, a patterned mask, and a nanowire. The graded planar buffer layer is on the substrate. The patterned mask is on the graded planar buffer layer and includes an opening through which the graded planar buffer layer is exposed. The nanowire is on the graded planar buffer layer in the opening of the patterned mask. A lattice constant of the graded planar buffer layer is between a lattice constant of the substrate and a lattice constant of the nanowire. By providing the graded planar buffer layer, lattice mismatch between the nanowire and the substrate can be reduced or eliminated, thereby improving the quality and performance of the nanowire structure.

Abstract: A method of fabricating a semiconductor-superconductor hybrid device comprises providing a workpiece comprising a semiconductor component, a layer of a first superconductor material on the semiconductor component, and a layer of a second superconductor material on the first superconductor material, the second superconductor material being different from the first superconductor material; etching the layer of the second superconductor material to expose a portion of the first superconductor material; and oxidising the portion of the first superconductor material to form a passivating layer on the semiconductor. The first superconductor provides energy coupling between the semiconductor and the second superconductor, and the passivating layer protects the semiconductor while allowing electrostatic access thereto. Also provided are a hybrid device, and a method of etching.

Abstract: A semiconductor-superconductor hybrid device comprises a semiconductor, a superconductor, and a barrier between the superconductor and the semiconductor. The device is configured to enable energy level hybridisation between the semiconductor and the superconductor. The barrier is configured to increase a topological gap of the device. The barrier allows for control over the degree of hybridisation between the semiconductor and the superconductor. Further aspects provide a quantum computer comprising the device, a method of manufacturing the device, and a method of inducing topological behaviour in the device.

Abstract: A hybrid heterostructure includes a semiconductor layer comprising indium antimonide, a superconductor layer comprising aluminum, and a screening layer between the semiconductor layer and the superconductor layer, the screening layer comprising indium arsenide. By including a screening layer of indium arsenide between the semiconductor layer of indium antimonide and the superconductor layer of aluminum, a high-performance and durable hybrid heterostructure suitable for use in quantum computing devices is provided.

Abstract: A quantum well field-effect transistor (QWFET) includes a barrier layer, a quantum well layer, and a spacer layer. The quantum well layer is on the barrier layer. The barrier layer and the spacer layer comprise aluminum indium antimonide that is undoped. The quantum well layer comprises indium antimonide. The spacer layer is on the quantum well layer. The quantum well layer and the spacer layer are between a source contact and a drain contact. A gate contact is on a dielectric layer, which is on the spacer layer. By providing the barrier layer and the spacer layer as undoped layers, a performance of the QWFET may be improved.

Abstract: A device comprising: a portion of semiconductor; a portion of superconductor arranged to a enable a topological phase having a topological gap to be induced in a region of the semiconductor by proximity effect; and a portion of a non-magnetic material comprising an element with atomic number Z greater than or equal to 26, arranged to increase the topological gap in the topological region of the semiconductor.