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Lateral GaN-based p-n junction gated field effect transistor (LJFET) power transistors on large area substrates were fabricated as a proof-of-concept to evaluate candidate power switching devices that could be designed with avalanche breakdown capability. The devices performed to design specifications aimed at demonstrating a device suitable for operation in cascode with a normally-off low-voltage Si based transistor companion. The maximum current density was 200 mA/mm and threshold voltage was [?]30V. Large gate width devices (40mm) exhibited >1A current. The devices have blocking capability to 800V. Initial testing of the switching dynamics indicates low dynamic RON even with an un-optimized buffer.

Gallium oxide (b-Ga2O3) is an emerging semiconductor with relevant properties for power electronics, solar-blind photodetectors, and some sensor applications due to its ultra-wide bandgap and developing technology base for high quality, melt-based substrate growth and thick, low-doped homoepitaxial layers. Of critical importance for the commercialization of this potentially important material is understanding of doping mechanisms in the monoclinic lattice, where two types of Ga sites and three types of O sites have been identified. A critical literature review of doping and defects of the monoclinic b-phase of gallium oxide is provided in this work. Theoretical fundamentals of both donor and acceptor doping in Ga2O3 are reviewed. Advances in doping of epitaxial Ga2O3 with a focus on molecular beam epitaxy and ion implantation are critically examined. As doping is fundamentally related to defects, particularly in this material, a review of defect characterization by optical and electrical spectroscopic methods is provided as well. P-type doping, one of the fundamental challenges for Ga2O3, is discussed in terms of first-principles calculations and ion implantation of known acceptors such as Mg and N.

Surface states that induce depletion regions are commonly believed to control the transport of charged carriers through semiconductor nanowires. However, direct, localized optical, and electrical measurements of ZnO nanowires show that native point defects inside the nanowire bulk and created at metal–semiconductor interfaces are electrically active and play a dominant role electronically, altering the semiconductor doping, the carrier density along the wire length, and the injection of charge into the wire. We used depth-resolved cathodoluminescence spectroscopy to measure the densities of multiple point defects inside ZnO nanowires, substitutional Cu on Zn sites, zinc vacancy, and oxygen vacancy defects, showing that their densities varied strongly both radially and lengthwise for tapered wires. These defect profiles and their variation with wire diameter produce trap-assisted tunneling and acceptor trapping of free carriers, the balance of which determines the low contact resistivity (2.6 × 10–3Ω·cm–2) ohmic, Schottky (Φ ≥ 0.35 eV) or blocking nature of Pt contacts to a single nano/microwire. We show how these defects can now be manipulated by ion beam methods and nanowire design, opening new avenues to control nanowire charge injection and transport.

Lateral GaN-based p-n junction gated field effect transistor (LJFET) power transistors on large area substrates were fabricated as a proof-of-concept to evaluate candidate power switching devices that could be designed with avalanche breakdown capability. The devices performed to design specifications aimed at demonstrating a device suitable for operation in cascode with a normally-off low-voltage Si based transistor companion. The maximum current density was 200 mA/mm and threshold voltage was −30V. Large gate width devices (40mm) exhibited >1A current. The devices have blocking capability to 800V. Initial testing of the switching dynamics indicates low dynamic RONeven with an un-optimized buffer.

Gallium oxide (β-Ga2O3) is an emerging semiconductor with relevant properties for power electronics, solar-blind photodetectors, and some sensor applications due to its ultra-wide bandgap and developing technology base for high quality, melt-based substrate growth and thick, low-doped homoepitaxial layers. Of critical importance for the commercialization of this potentially important material is understanding of doping mechanisms in the monoclinic lattice, where two types of Ga sites and three types of O sites have been identified. A critical literature review of doping and defects of the monoclinic β-phase of gallium oxide is provided in this work. Theoretical fundamentals of both donor and acceptor doping in Ga2O3are reviewed. Advances in doping of epitaxial Ga2O3with a focus on molecular beam epitaxy and ion implantation are critically examined. As doping is fundamentally related to defects, particularly in this material, a review of defect characterization by optical and electrical spectroscopic methods is provided as well. P-type doping, one of the fundamental challenges for Ga2O3, is discussed in terms of first-principles calculations and ion implantation of known acceptors such as Mg and N.