Abstract: A nanowire comprises a polar semiconductor material that is compositionally graded along the nanowire from a first end to a second end to define a polarization doping profile along the nanowire from the first end to the second end. The polar semiconductor material may comprise a group IH-nitride semiconductor, such as an alloy of GaN and AlN, or an alloy of GaN and InN. Such nanowires may be formed by nucleating the first ends on a substrate, growing the nanowires by depositing polar semiconductor material on the nucleated first ends on a selected growth face, and compositionally grading the nanowires during growth to impart the polarization doping. The direction of the compositional grading may be reversed during the growing of the nanowires to reverse the type of the imparted polarization doping. In some embodiments, the reversing forms n/p or p/n junctions in the nanowires.

Abstract: A method of manufacturing a heterostructure device is provided that includes implantation of ions into a portion of a surface of a multi-layer structure. Iodine ions are implanted between a first region and a second region to form a third region. A charge is depleted from the two dimensional electron gas (2DEG) channel in the third region to form a reversibly electrically non-conductive pathway from the first region to the second region. On applying a voltage potential to a gate electrode proximate to the third region allows electrical current to flow from the first region to the second region.

Abstract: A heterostructure device includes a semiconductor multi-layer structure that has a first region, a second region and a third region. The first region is coupled to a source electrode and the second region is coupled to a drain electrode. The third region is disposed between the first region and the second region. The third region provides a switchable electrically conductive pathway from the source electrode to the drain electrode. The third region includes iodine ions. A system includes a heterostructure field effect transistor that includes the device.

Abstract: A novel enhancement mode field effect transistor (FET), such as a High Electron Mobility Transistors (HEMT), has an N-polar surface uses polarization fields to reduce the electron population under the gate in the N-polar orientation, has improved dispersion suppression, and low gate leakage.

Abstract: A method for fabricating nitrogen-face (N-face) nitride-based electronic devices with low buffer leakage, comprising isolating a buffer from a substrate with an AlGaInN nucleation layer to suppress impurity incorporation from the substrate into the buffer. A method for fabricating N-face nitride-based electronic devices with low parasitic resistance and high breakdown, comprising capping a device structure with a conductive layer to provide extremely low access and/or contact resistances, is also disclosed.

Abstract: A novel enhancement mode field effect transistor (FET), such as a High Electron Mobility Transistors (HEMT), has an N-polar surface uses polarization fields to reduce the electron population under the gate in the N-polar orientation, has improved dispersion suppression, and low gate leakage.

Abstract: A heterostructure device includes a semiconductor multi-layer structure that has a first region, a second region and a third region. The first region is coupled to a source electrode and the second region is coupled to a drain electrode. The third region is disposed between the first region and the second region. The third region provides a switchable electrically conductive pathway from the source electrode to the drain electrode. The third region includes iodine ions. A system includes a heterostructure field effect transistor that includes the device.

Abstract: A heterostructure device or article includes a carrier transport layer, a back channel layer and a barrier layer. The carrier transport layer has a first surface and a second surface opposing to the first surface. The back channel layer is secured to the first surface of the carrier transport layer and the barrier layer is secured to the second surface of the carrier transport layer. Each of the carrier transport layer, the back channel layer and the barrier layer comprises an aluminum gallium nitride alloy. The article further includes a 2D electron gas at an interface of the second surface of the carrier transport layer and a surface of the barrier layer. The 2D electron gas is defined by a bandgap differential at an interface, which allows for electron mobility. A system includes a heterostructure field effect transistor that includes the article.

Abstract: Novel GaN/AlGaN metal-semiconductor field-effect transistor (MESFET) structures grown without any impurity doping in the channel. A high-mobility polarization-induced bulk channel charge is created by grading the channel region linearly from GaN to Al0.3Ga0.7N over a distance, e.g., 1000 ?. A polarization-doped field effect transistor (PolFET) was fabricated and tested under DC and RF conditions. A current density of 850 mA/mm and transconductance of 93 mS/mm was observed under DC conditions. Small-signal characterization of 0.7 ?m gate length devices had a cutoff frequency, f?=19 GHz, and a maximum oscillation of fmax=46 GHz. The PolFETs perform better than comparable MESFETs with impurity-doped channels, and are suitable for high microwave power applications. An important advantage of these devices over AlGaN/GaN HEMTs is that the transconductance vs. gate voltage profile can be tailored by compositional grading for better large-signal linearity.

Abstract: A method for fabricating III-N semiconductor devices on the N-face of layers comprising (a) growing a III-nitride semiconductor device structure in a Ga-polar direction on a substrate, (b) attaching a Ga face of the III-nitride semiconductor device structure to a host substrate, and (c) removing the substrate to expose the N-face surface of the III-nitride semiconductor device structure. An N-polar (000-1) oriented III-nitride semiconductor device is also disclosed, comprising one or more (000-1) oriented nitride layers, each having an N-face opposite a group III-face, wherein at least one N-face is an at least partially exposed N-face, and a host substrate attached to one of the group III-faces.

Abstract: A method for fabricating nitrogen-face (N-face) nitride-based electronic devices with low buffer leakage, comprising isolating a buffer from a substrate with an AlGaInN nucleation layer to suppress impurity incorporation from the substrate into the buffer. A method for fabricating N-face nitride-based electronic devices with low parasitic resistance and high breakdown, comprising capping a device structure with a conductive layer to provide extremely low access and/or contact resistances, is also disclosed.

Abstract: Novel GaN/AlGaN metal-semiconductor field-effect transistor (MESFET) structures grown without any impurity doping in the channel. A high-mobility polarization-induced bulk channel charge is created by grading the channel region linearly from GaN to Al0.3Ga0.7N over a distance, e.g., 1000 ?. A polarization-doped field effect transistor (PolFET) was fabricated and tested under DC and RF conditions. A current density of 850 mA/mm and transconductance of 93 mS/mm was observed under DC conditions. Small-signal characterization of 0.7 ?m gate length devices had a cutoff frequency, ƒ?=19 GHz, and a maximum oscillation of ƒmax=46 GHz. The PolFETs perform better than comparable MESFETs with impurity-doped channels, and are suitable for high microwave power applications. An important advantage of these devices over AlGaN/GaN HEMTs is that the transconductance vs. gate voltage profile can be tailored by compositional grading for better large-signal linearity.