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Creators/Authors contains: "Simin, Grigory"

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  1. ; ; ; ; ; ; (, Japanese Journal of Applied Physics)
    Abstract In this paper we present a study of distribution polarization doped AlxGa1−xN layers and their use in quasi-vertical configuration pn-diodes which exhibited a high breakdown field of ∼8.5 MV cm−1and a large forward current density (∼23 kA cm−2). We also establish their potential use in UVC light emitters by studying the optical emission from a quantum well inserted at the distribution polarization doped pn-junction interface. 
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    Free, publicly-accessible full text available May 1, 2026
  2. ; ; ; ; ; (, Micromachines)
    Wengang, Bi; Haiding, Sun (Ed.)
    An extreme bandgap Al0.64Ga0.36N quantum channel HEMT with Al0.87Ga0.13N top and back barriers, grown by MOCVD on a bulk AlN substrate, demonstrated a critical breakdown field of 11.37 MV/cm—higher than the 9.8 MV/cm expected for the channel’s Al0.64Ga0.36N material. We show that the fraction of this increase is due to the quantization of the 2D electron gas. The polarization field maintains electron quantization in the quantum channel even at low sheet densities, in contrast to conventional HEMT designs. An additional increase in the breakdown field is due to quantum-enabled real space transfer of energetic electrons into high-Al barrier layers in high electric fields. These results show the advantages of the quantum channel design for achieving record-high breakdown voltages and allowing for superior power HEMT devices. 
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  3. ; ; ; ; ; ; (, Applied Physics Express)
    Abstract We report threshold voltage (VTH) control in ultrawide bandgap Al0.4Ga0.6N-channel metal oxide semiconductor heterostructure field-effect transistors using a high-temperature (300 °C) anneal of the high-kZrO2gate-insulator. Annealing switched the polarity of the fixed charges at the ZrO2/AlGaN interface from +5.5 × 1013cm−2to −4.2 × 1013cm−2, pinningVTHat ∼ (−12 V), reducing gate leakage by ∼103, and improving subthreshold swing 2× (116 mV decade−1). It also enabled the gate to repeatedly withstand voltages from −40 to +18 V, allowing the channel to be overdriven doubling the peak currents to ∼0.5 A mm−1. 
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  4. ; ; ; ; ; (, Applied Physics Express)
    Abstract We demonstrate fully fabricated AlGaN/GaN high electron mobility transistors (HEMTs) transferred from sapphire to copper tape on flexible polyethylene terephthalate using 193 nm excimer laser liftoff (LLO). The heterojunction is structurally intact after LLO, leading to preserved electron mobility μ n ∼1630 cm 2 V −1 s −1 and carrier concentration n s ∼10 13 cm −2 . The maximum drain saturation current decreased by ∼18% after transfer, which is a lower reduction than other reported transfer methods. The drain current of this flexible HEMT increased monotonically under tensile stress applied using a convex-shaped plate, while the threshold voltage shifted more negative in quantitative agreement with the expected piezoelectric charge for an intact heterojunction. 
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  5. ; ; ; ; ; ; (, Applied Physics Express)
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  6. ; ; ; ; ; ; (, ECS Meeting Abstracts)
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  7. ; ; ; ; ; (, Applied Physics Letters)
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  8. ; ; ; ; ; ; ; ; ; (, Applied Physics Letters)
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  9. ; ; ; ; ; ; (, Applied Physics Express)
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  10. ; ; ; ; ; ; (, Applied Physics Letters)
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