A5070521093- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- ZnO doping and properties
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- 2D Materials and Applications
- Metal and Thin Film Mechanics
- Mechanical and Optical Resonators
- Near-Field Optical Microscopy
- Magnetic properties of thin films
- Advanced Thermoelectric Materials and Devices
- Iron-based superconductors research
- Radioactive contamination and transfer
- Semiconductor materials and interfaces
- Plasmonic and Surface Plasmon Research
- Surface and Thin Film Phenomena
- Copper-based nanomaterials and applications
- Magnetic Properties and Applications
- Photonic Crystals and Applications
- Silicon and Solar Cell Technologies
- Thermal Radiation and Cooling Technologies
- Magnetic Properties of Alloys
University of California, San Diego
2023
Collaborative Innovation Center of Advanced Microstructures
2004-2020
Nanjing University
2005-2020
Fudan University
2019
China Academy of Engineering Physics
2018
Tokyo Institute of Technology
2013
University of Nebraska–Lincoln
2010-2012
National Laboratory of Solid State Microstructures
2004-2011
CeO2 nanoparticles were prepared by a simple co-precipitation method and the structural magnetic properties studied. X-ray diffraction, Raman selected area electron diffraction results indicate that samples have cubic fluorite structure without other impurity phases. Magnetisation measurements calcined at different temperatures exhibit room temperature ferromagnetism (RTFM). The result of energy-dispersed spectrometry (EDS) analysis indicates ferromagnetic impurities could not be responsible...
A high-performance Al0.1Ga0.9N ultraviolet (UV) avalanche photodiode (APD) with a separate absorption and multiplication structure grown on AlN templates is fabricated by employing triple-mesa structure. The AlGaN UV-APD exhibits maximum gain up to 2.3 × 104 at the reverse bias of 67 V low breakdown voltage (<70 V). confirmed significantly lower reduce sidewall leakage current in comparison conventional double-mesa one. These improvements are explained simulation electric field which...
The performances of InGaN Schottky photodetectors with varied fabrication processes were investigated. photoresponse and dark current can be obviously improved by inserting a thin Si3N4 passivation layer between the metal. Furthermore, mesa process gives not only further increase in but also pronounced reduction reverse leakage about two orders magnitude. A lateral surface mechanism associated 2-D variable-range hopping conduction through high-density states is proposed to explain after etching mesa.
We report the first demonstration of a GaN-based planar metal-semiconductor-metal (MSM) ultraviolet (UV) avalanche photodiode (APD). The MSM APD with semitransparent interdigitated Schottky electrodes is fabricated on low-defect-density GaN homoepitaxial layer grown bulk substrate by metal-organic chemical vapor deposition. dislocation density homoepilayer characterized cathodoluminescence mapping technique ~ 5 ×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Centrosymmetric (CS) nonmagnetic materials with hidden spin polarization induced by non-CS site symmetries and spin-orbit coupling are promising candidates for spintronic applications, in light of the zero net modulatable effects local structures. There is, however, an open issue regarding possible splitting broken inversion symmetry at sample surface. Here, we performed combinatorial experimental theoretical studies on potentially $2H\text{\ensuremath{-}}\mathrm{MoT}{\mathrm{e}}_{2}$ its...
We report an effect that occurs in semiconductors where internal electrical fields interact with a temperature gradient. Steady current vortices and magnetic field develop the system, even without external carrier injection. The is electrodynamic, energy dissipative, fundamentally distinct from any previously described electrothermal effects. In bipolar structures effective thermopower can be significantly modified by vortices. Joule heating arising reduces thermal conductivity amount...
The performance of hard-magnetic nanostructures is investigated by analyzing the size and geometry dependence thin-film hysteresis loops. Compared to bulk magnets, weight volume are much less important, but we find that energy product remains main figure merit down very small features sizes. However, loops easier control on length scales, as epitomized Fe-Co-Pt thin films with magnetizations up 1.78 T coercivities 2.52 T. Our numerical analytical calculations show feature have a big effect...
Weak anti-localization of the two-dimensional electron gas (2DEG) in a modulation-doped Al0.22Ga0.78N∕GaN single heterostructure has been investigated through magnetoresistance measurements at low temperatures. The elastic scattering time τe, dephasing τϕ and spin-orbit τso various temperatures are obtained. When second subband triangular quantum well heterointerface is occupied by 2DEG, weak observed clearly, which thought to be due strong effect induced intersubband scattering. become...
Microwave impedance microscopy (MIM) is a near-field imaging technique that has been used to visualize the local conductivity of materials with nanoscale resolution across GHz regime. In recent years, MIM shown great promise for investigation topological states matter, correlated electronic states, and emergent phenomena in quantum materials. To explore these low-energy phenomena, many which are only detectable milliKelvin regime, we have developed novel low-temperature incorporated into...
A pronounced hump structure at about −5 V in the high-frequency capacitance-voltage (C-V) curve of an undoped InGaN/GaN heterostructure is observed and this weakens gradually with decreasing measurement frequency, indicating occurrence inversion behavior heterostructure. The C-V attributed to hole accumulation heterointerface where a well formed due strong piezoelectric polarization effect acceptor traps related Ga vacancies InGaN layer are thought be source minority carriers. theoretical...
A phenomenological model is presented to determine the experimental value of spontaneous polarization GaN. The expression at room temperature obtained. electrostrictive coefficient M33 a wurtzite GaN film used evaluate exact can be obtained as long single crystal zinc blende measured. also values in other III-V nitrides, AlN and InN.
Novel multifunctional superparamagnetic and optical nanohybrids are fabricated for biomedical applications. This architecture involves a silica core surrounded by thin shell of FePt that is further covered with an outer gold. Polyethyleneimine was utilized as linker to bridge the gold shell, which allowed 3-nm nanoparticle seeds be loaded uniform formed. These doubly coated nanoparticles take advantage tunable resonance absorption in visible near-infrared (NIR) ranges can controlled using...
The mesoscopic Kondo effect in metallic nanoparticles containing a magnetic impurity is investigated by model calculations. A Maxwell–Garnett approach used to approximately determine the resistivity of doped matrix, and susceptibility estimated from confinement conduction electrons. Conductivity measurements embedded matrix are difficult realize, because matrices distort cloud, whereas insulating or semiconducting yield very weak signal. By comparison, do not suffer these shortcomings....
Un-doped and 5% Co-doped ZnO powders were prepared by sol-gel method using Zn(CH/sub 3/COOH)/sub 2//spl middot/2H/sub 2/O Co(CH/sub as starting precursors ethanol a solvent, the heated at 550/spl deg/C for 30 minutes in air. In this paper, methods such X-ray diffraction (XRD), Raman vibrating sample magnetometer (VSM), we have compared un-doped powder to study structure magnetic properties of powder. The XRD patterns showed that no second phase appeared change wurtzite ZnO, which indicated...
Schrodinger equation and Poisson are solved self-consistently for Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</sub> Ga N/GaN heterojunctions grown along the c axis, then distribution of electrons exact energy all bounded states confined in gotten, found to take up first two subbands. Considerable magnitude Rashba spin splitting subband at Fermi level is obtained. The changes with barrier thickness, doping concentration calculated....