Abstract: A device includes a Schottky barrier formed by a metal-semiconductor junction between a semiconductor nanowire and a metal contact. The metal contact at least partly encloses a circumferential area of each nanowire along the length thereof. The nanowire includes a low doped region that is part of the metal-semiconductor junction. The device can be fabricated using a method where two different growth modes are used, the first step including axial growth from a substrate giving a suitable template for formation of the metal-semiconductor junction, and the second step including radial growth enabling control of the doping levels in the low doped region.

Abstract: The present invention relates to providing layers of different thickness on vertical and horizontal surfaces (15, 20) of a vertical semiconductor device (1). In particular the invention relates to gate electrodes and the formation of precision layers (28) in semiconductor structures comprising a substrate (10) and an elongated structure (5) essentially standing up from the substrate. According to the method of the invention the vertical geometry of the device (1) is utilized in combination with either anisotropic deposition or anisotropic removal of deposited material to form vertical or horizontal layers of very high precision.

Abstract: The present invention provides a photodiode comprising a p-i-n or pn junction at least partly formed by first and second regions (2) made of semiconductor materials having opposite conductivity type, wherein the p-i-n or pn junction comprises a light absorption region (11) for generation of charge carriers from absorbed light. One section of the p-i-n or pn junction is comprises by one or more nanowires (7) that are spaced apart and arranged to collect charge carriers generated in the light absorption region (11). At least one low doped region (10) made of a low doped or intrinsic semiconductor material provided between the nanowires (7) and one of said first region (1) and said second region (2) enables custom made light absorption region and/or avalanche multiplication region of the active region (9).

Abstract: The present invention relates to epitaxial growth of nanowires on a substrate. In particular the invention relates to growth of nanowires on an Si-substrate without using Au as a catalyst. In the method according to the invention an oxide template is provided on a passivated surface of the substrate. The oxide template defines a plurality of nucleation onset positions for subsequent nanowire growth. According to one embodiment a thin organic film is used to form the oxide template.

Abstract: The present invention relates to the growing of nitride semiconductors, applicable for a multitude of semiconductor devices such as diodes, LEDs and transistors. According to the method of the invention nitride semiconductor nanowires are grown utilizing a CVD based selective area growth technique. A nitrogen source and a metal-organic source are present during the nanowire growth step and at least the nitrogen source flow rate is continuous during the nanowire growth step. The V/III-ratio utilized in the inventive method is significantly lower than the V/III-ratios commonly associated with the growth of nitride based semiconductor.

Abstract: The present invention relates to the growing of nitride semiconductors, applicable for a multitude of semiconductor devices such as diodes, LEDs and transistors. According to the method of the invention nitride semiconductor nanowires are grown utilizing a CVD based selective area growth technique. A nitrogen source and a metal-organic source are present during the nanowire growth step and at least the nitrogen source flow rate is continuous during the nanowire growth step. The V/III-ratio utilized in the inventive method is significantly lower than the V/III-ratios commonly associated with the growth of nitride based semiconductor.

Abstract: The present invention relates to a substrate (5) comprising a Si-base (1) and an InAs-layer (4) provided on said Si-base where said InAs-layer (4) has a thickness between 100 and 500 nanometers and root-mean-square roughness of the upper surface of said InAs-layer (4) is below 1 nanometer. The invention further relates to a method for forming said substrate. The invention also relates to growing InAs-nanowires (7) as well as a GaSb-layer (17) on said substrate (5).

Abstract: The invention relates to a nanowire device for manipulation of charged molecules, comprising a tubular nanowire with a through-going channel; a plurality of individually addressable wrap gate electrodes arranged around said tubular nanowire with a spacing between each two adjacent wrap gate electrodes and means for connecting the wrap gate electrodes to a voltage source. The invention further relates to a nanowire system comprising at least one nanowire device, and to a method for manipulating of charged molecules within a through-going channel of a tubular nanowire.

Abstract: The present invention relates to providing layers of different thickness on vertical and horizontal surfaces (15, 20) of a vertical semiconductor device (1). In particular the invention relates to gate electrodes and the formation of precision layers (28) in semiconductor structures comprising a substrate (10) and an elongated structure (5) essentially standing up from the substrate. According to the method of the invention the vertical geometry of the device (1) is utilized in combination with either anisotropic desposition or anisotropic removal of deposited material to form vertical or horizontal layers of very high precision.

Abstract: The present invention provides a method for aligning nanowires which can be used to fabricate devices comprising nanowires that has well-defined and controlled orientation independently on what substrate they are arranged on. The method comprises the steps of providing nanowires (1) and applying an electrical field (E) over the population of nanowires (1), whereby an electrical dipole moment of the nanowires makes them align along the electrical field (E). Preferably the nanowires are dispersed in a fluid during the steps of providing and aligning. When aligned, the nanowires can be fixated, preferably be deposition on a substrate (2). The electrical field can be utilised in the deposition. Pn-junctions or any net charge introduced in the nanowires (1) may assist in the aligning and deposition process. The method is suitable for continuous processing, e.g. in a roll-to-roll process, on practically any substrate materials and not limited to substrates suitable for particle assisted growth.

Abstract: The present invention relates to semiconductor devices comprising semiconductor nanoelements. In particular the invention relates to devices having a volume element having a larger diameter than the nanoelement arranged in epitaxial connection to the nanoelement. The volume element is being doped in order to provide a high charge carrier injection into the nanoelement and a low access resistance in an electrical connection. The nanoelement may be upstanding from a semiconductor substrate. A concentric layer of low resistivity material forms on the volume element forms a contact.

Abstract: A resonant tunneling diode, and other one dimensional electronic, photonic structures, and electromechanical MEMS devices, are formed as a heterostructure in a nanowhisker by forming length segments of the whisker with different materials having different band gaps.

Abstract: The present invention provides a method and a system for forming wires (1) that enables a large scale process combined with a high structural complexity and material quality comparable to wires formed using substrate-based synthesis. The wires (1) are grown from catalytic seed particles (2) suspended in a gas within a reactor. Due to a modular approach wires (1) of different configuration can be formed in a continuous process. In-situ analysis to monitor and/or to sort particles and/or wires formed enables efficient process control.

Abstract: The present invention relates to the growing of nitride semiconductors, applicable for a multitude of semiconductor devices such as diodes, LEDs and transistors. According to the method of the invention nitride semiconductor nanowires are grown utilizing a CVD based selective area growth technique. A nitrogen source and a metal-organic source are present during the nanowire growth step and at least the nitrogen source flow rate is continuous during the nanowire growth step. The V/III-ratio utilized in the inventive method is significantly lower than the V/III-ratios commonly associated with the growth of nitride based semiconductor.

Abstract: A method for forming a nanowhisker of, e.g., a III-V semiconductor material on a silicon substrate, comprises: preparing a surface of the silicon substrate with measures including passivating the substrate surface by HF etching, so that the substrate surface is essentially atomically flat. Catalytic particles on the substrate surface are deposited from an aerosol; the substrate is annealed; and gases for a MOVPE process are introduced into the atmosphere surrounding the substrate, so that nanowhiskers are grown by the VLS mechanism. In the grown nanowhisker, the crystal directions of the substrate are transferred to the epitaxial crystal planes at the base of the nanowhisker and adjacent the substrate surface.

Abstract: The present invention relates to light emitting diodes comprising at least one nanowire. The LED according to the invention is an upstanding nanostructure with the nanowire protruding from a substrate. A bulb with a larger diameter than the nanowire is arranged in connection to the nanowire and at an elevated position with regards to the substrate. A pn-junction is formed by the combination of the bulb and the nanowire resulting in an active region to produce light.

Abstract: The present invention relates to nanoscaled electronic devices with a vertical nanowire as a functional part. Contacts are arranged on the nanowire at different parts of the nanowire, for example drain and source contacts. In connection to the nanowire contacts are external electrodes, that connect at different levels, as seen from the substrate, of the device. The external electrodes are elongated, and typically and preferably stripe-like. According to the invention a first external electrode, or contacts, associated with contact(s) at a first part of the nanowire, and a second external electrode, associated with contact(s) at a second part of the nanowire are arranged in a cross-bar configuration. The cross-bar configuration minimizes the overlay of the external electrodes, hence, parasitic capacitances and current leakage can be reduced, and the performance of the device improved.

Abstract: A nanowire wrap-gate transistor is realized in a semiconductor material with a band gap narrower than Si. The strain relaxation in the nanowires allows the transistor to be placed on a large variety of substrates and heterostructures to be incorporated in the device. Various types of heterostructures should be introduced in the transistor to reduce the output conductance via reduced impact ionization rate, increase the current on/off ratio, reduction of the sub-threshold slope, reduction of transistor contact resistance and improved thermal stability. The parasitic capacitances should be minimized by the use of semi-insulating substrates and the use of cross-bar geometry between the source and drain access regions. The transistor may find applications in digital high frequency and low power circuits as well as in analogue high frequency circuits.

Abstract: The present invention relates to the growing of nitride semiconductors, applicable for a multitude of semiconductor devices such as diodes, LEDs and transistors. According to the method of the invention nitride semiconductor nanowires are grown utilizing a CVD based selective area growth technique. A nitrogen source and a metal-organic source are present during the nanowire growth step and at least the nitrogen source flow rate is continuous during the nanowire growth step. The V/III-ratio utilized in the inventive method is significantly lower than the V/III-ratios commonly associated with the growth of nitride based semiconductor.

Abstract: The present invention relates to light emitting diodes, LEDs. In particular the invention relates to a LED comprising a nanowire as an active component. The nanostructured LED according to the embodiments of the invention comprises a substrate and at an upstanding nanowire protruding from the substrate. A pn-junction giving an active region to produce light is present within the structure. The nanowire, or at least a part of the nanowire, forms a wave-guiding section directing at least a portion of the light produced in the active region in a direction given by the nanowire.