- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Opto-electrical Properties of GaN/Si Nanoheterostructure Array Device
摘要： A GaN/Si nanoheterostructure array was synthesized using the functional substrate of silicon nanoporous pillar array (Si-NPA) by CVD method. An n-GaN nanocolumnar/p-Si nanocrystalline nanoheterojuction array solar cell was fabricated and the GaN nanocolumnar grew along the [0001] direction. The device has an average integrated reflection of ~4.79% at the range of 300-1200 nm. The solar cell showed a Voc of 0.82 V, a Jsc of 23.21 mA, a FF of 38.3% and a maximum power conversion efficiency of 7.29%. The results provide a new conception of mass-nanoheterojuctions for photovoltaic filed.
关键词： Solar cells,Gallium nitride (GaN),Nanoheterostructure array,Silicon nanoporous pillar array (Si-NPA)
更新于2025-09-11 14:15:04
-
Growth of Gallium Nitride Micro- and Nanocrystallites on the Surface of Gallium Arsenide
摘要： As a result of heterosegregation, we have obtained a gallium nitride phase, including oriented micro- and nanocrystallites, on the surface of gallium arsenide. The mechanism underlying the growth of crystallites of the surface phase has been analyzed.
关键词： gallium nitride film,gallium arsenide,surface heterosegregation
更新于2025-09-10 09:29:36
-
Hot-Electron Trapping and Hole-Induced Detrapping in GaN-Based GITs and HD-GITs
摘要： This paper investigates the trapping mechanisms in gate-injection transistors (GITs) without and with a pdrain electrode, referred to as GITs and Hybrid-Drain-embedded GITs (HD-GITs), respectively, used to inject holes and reduce charge trapping effects. We compare the two sets of devices under both the OFF-state and semi-ON state, to investigate the role of hot electrons in favoring the charge trapping. The analysis is based on combined pulsed characterization, transient measurements, and electroluminescence (EL) characterization. We demonstrate the following relevant results: 1) GITs and HD-GITs have comparable and negligible dynamic RON when trapping is induced in the OFF-state; under semi-ON state conditions, GITs suffer from significant dynamic RON, while HD-GITs show no additional trapping with respect to OFF-state; 2) EL characterization carried out until VDS = 500 V in semi-ON conditions shows comparable features, suggesting that the electric field and hot-carrier density are similar in GITs and HD-GITs. This result indicates that the hot-electron trapping rate is identical for the two sets of samples, so the difference observed in dynamic RON must be ascribed to a different detrapping rate; 3) transient RON measurements indicate that the traps filled in the OFF-state conditions are the same as those filled by hot electrons in semi-ON, with Ea = 0.8 eV (possibly CN); and 4) EL analysis under constant bias indicates that in GITs there is a time-dependent increase in the luminescence signal at the drain terminal, when the devices are biased with VDS = 300 V. Such effect, indicative of hot-electron trapping, is not observed in HD-GITs. Based on the experimental evidence collected within this paper, we conclude that—in the semi-ON state—the main difference between GITs and HD-GITs consists in a faster detrapping rate of hot electrons, achieved through hole injection from the pdrain terminal.
关键词： gate-injection transistors (GITs),Electroluminescence (EL),gallium nitride (GaN) HEMT,trapping,hot electron
更新于2025-09-10 09:29:36
-
Analytical model for accurate extraction of metal-semiconductor ohmic contact parameters using a novel electrode-pair layout scheme
摘要： In this paper, an electrode-pair model is proposed and demonstrated for the first time to accurately extract the electrical resistance parameters of the planar metal-semiconductor ohmic contacts. Different from the conventional transmission line model, the proposed model layout features a series of separated electrode pairs with the same electrode distance but various widths. Meanwhile, an equivalent circuit for contact resistance composition is set up to clearly specify the contribution of each resistance component to the overall contact performance. The semiconductor sheet resistances underneath the contact and outside the contact area are treated as completely independent variables. The proposed scheme is modeled theoretically and analyzed by the TCAD simulations, and the validity of the model is verified by the experimental data. Finally, the variance of the sheet resistance underneath the contact after annealing treatment can be distinguished by the model and hence more actual and precise specific contact resistance is achieved. This work provides a distinct perspective to understand and quantify the electrical characteristics of the semiconductor ohmic contacts, and it can also assist engineers for a better electrode layout design.
关键词： Ohmic contacts,Gallium Nitride,Semiconductor devices,Modeling process
更新于2025-09-10 09:29:36
-
[IEEE 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Budapest, Hungary (2018.8.26-2018.8.30)] 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Controller Design of a New Universal Two-Phase SiC-GaN-Based DC-DC Converter for Plug-in Electric Vehicles
摘要： Wide Band Gap (WBG) semiconductor technologies such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are being replaced with Silicon (Si) MOSFETs and IGBTs in power switching converters. In hard-switching applications, GaN is more attractive because of its lower switching power losses. The DC-DC power module of the motor drive in Plug-In Electric Vehicles (PEVs) has a power rating range of 30-150 kW while the power rating of GaN is not that much high. A two-phase SiC-GaN-based converter can satisfy the demanded power, achieving the advantage of WBG technology, and avoid the complexity of multi-phase converter with high number of phases. Obtaining the maximum efficiency, the power sharing is not symmetrical. Therefore, a cascade controller is considered in this paper to control fully directional universal converter: drive/plug-in, boost/buck mode. The simulation results prove the satisfactory performance of the controller in all modes of operation.
关键词： Silicon Carbide,Plug-In Electric Vehicles,Universal DC-DC Converter,Cascade Controller,Gallium Nitride
更新于2025-09-10 09:29:36
-
Spin-Polarized Positron Annihilation Measurement on Ga Vacancies in p-type GaN
摘要： Nitrogen-implanted p-type GaN (cid:12)lms have been investigated through the Doppler broadening of annihilation radiation (DBAR) measurements with spin-polarized positrons and magnetization (M {H) measurements. The DBAR spectra showed asymmetry upon magnetic-(cid:12)eld reversal at 300 K, while no asymmetry appeared at 30 K. This result indicates that excess electron spins at Ga vacancies are aligned under the application of magnetic (cid:12)eld at 300 K, but such spin ordering vanishes at low temperatures. No hysteresis was found in M {H curves both at 10 K and 300 K. This means that no macroscopic magnetism appears even though excess electron spins at Ga vacancies are introduced.
关键词： Positron spectroscopy,Ion implantation methods,Gallium nitride
更新于2025-09-10 09:29:36
-
[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Nonlinear Quasi-Phase Matching with metasurfaces
摘要： Quasi-Phase Matching is an optical process needed to build up nonlinear signal from strong pump intensity and is generally obtained through periodical inversion of coherence domains of the crystal. We show that this effect can be arti?cially monitored through inserting metasurfaces along the optical path of the light in a waveguide. Sub-wavelength gratings of holes are etched in Gallium Nitride to locally change medium dispersion, allowing continuous increase of the second harmonic signal. This approach can be used to address any phase delay difference between pump and signal at will, not only π, opening up new perspectives for arbitrary phase matching conditions. It can also be implemented in highly nonlinear systems, in which it is generally hard to address phase-matching conditions, for instance waveguides with buried intersubband quantum wells or other materials such GaAs.
关键词： second harmonic generation,metasurfaces,Quasi-Phase Matching,Gallium Nitride,nonlinear optics
更新于2025-09-09 09:28:46
-
Full W-Band GaN Power Amplifier MMICs Using a Novel Type of Broadband Radial Stub
摘要： In this paper, we describe the design of the first reported full W-band (75–110 GHz) power amplifier (PA) monolithic microwave integrated circuits (MMICs) based on gallium nitride technology. The discussed MMICs come in two versions. Over a bandwidth (BW) of 70–110 GHz, the three-stage PA can deliver, on average, 25.6 dBm with a power-added efficiency (PAE) of 6.5%, while the four-stage PA is able to generate 27 dBm with a PAE of 6.1%. A peak output power of 28.6 dBm is achieved at 80 GHz with a PAE of 8.6%, which corresponds to a power density of 2.6 W/mm. The significant BW was achieved partially by incorporating a novel type of broadband radial stub into the design, which can provide nearly a twofold rejection-BW improvement over the conventional version. To the best of our knowledge, no other solid-state circuit can deliver such power levels over the complete W-band.
关键词： monolithic microwave integrated circuit (MMIC),Broadband,power amplifier (PA),high-electron-mobility transistor (HEMT),W-band (75–110 GHz),radial stub,gallium nitride,millimeter-waves (mm-waves)
更新于2025-09-09 09:28:46
-
Degradation of GaN-on-GaN vertical diodes submitted to high current stress
摘要： GaN-on-GaN vertical devices are expected to ?nd wide application in power electronics, thanks to the high current densities, the low on-resistance and the high breakdown voltage. So far, only few papers on the reliability of GaN-on-GaN vertical devices have been published in the literature. This paper investigates the degradation of GaN-on-GaN pn diodes submitted to stress at high current density. The study was carried out by means of electrical characterization and electroluminescence (EL) measurements. We demonstrate that: (i) when submitted to stress at high current density, the devices show signi?cant changes in the electrical characteristics: an increase in on-resistance/turn-on voltage, an increase in the generation/recombination components, the creation of shunt-paths. (ii) the increase in on-resistance is strongly correlated to the decrease in the EL signal emitted by the diodes. (iii) the degradation kinetics have a square-root dependence on time, indicative of a di?usion process. The results are interpreted by considering that stress induces a di?usion of hydrogen from the highly-p-type doped surface towards the pn junction. This results in a decrease in hole concentration, due to the creation of MgeH bonds, and in a lower hole injection. As a consequence, on-resistance increases while EL signal shows a correlated decrease.
关键词： Wide band gap semiconductors,Bulk GaN substrates,Vertical diodes,pn junction,Di?usion,Gallium nitride,Hydrogen,Degradation
更新于2025-09-09 09:28:46
-
RF Performance of Al0.85Ga0.15N/Al0.70Ga0.30N High Electron Mobility Transistors with 80 nm Gates
摘要： Al-rich AlGaN-channel high electron mobility transistors (HEMTs) with 80 nm long gates and 85% (70%) Al in the barrier (channel) were evaluated for RF performance. DC characteristics include a maximum current of 160 mA/mm with transconductance of 24 mS/mm, limited by source and drain contacts, and an on/off current ratio of 109. fT of 28.4 GHz and fMAX of 18.5 GHz were determined from small-signal S-parameter measurements. Output power density of 0.38 W/mm was realized at 3 GHz in a power sweep using on-wafer load pull techniques.
关键词： high electron mobility transistor,Ultra-wide-bandgap,RF performance,HEMT,aluminum gallium nitride
更新于2025-09-09 09:28:46