A5037644324- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Semiconductor materials and devices
- Semiconductor Quantum Structures and Devices
- ZnO doping and properties
- Metal and Thin Film Mechanics
- Semiconductor materials and interfaces
- Acoustic Wave Resonator Technologies
- Photocathodes and Microchannel Plates
- Quantum and electron transport phenomena
- Nanowire Synthesis and Applications
- Silicon Carbide Semiconductor Technologies
- Plasma Diagnostics and Applications
- Phytochemical compounds biological activities
- Power Line Inspection Robots
- Robotics and Sensor-Based Localization
- Insect Utilization and Effects
- Spectroscopy and Laser Applications
- 2D Materials and Applications
- Graphene research and applications
- Silicon and Solar Cell Technologies
- Advanced Welding Techniques Analysis
- Advancements in Semiconductor Devices and Circuit Design
- Aluminum Alloy Microstructure Properties
- Antimicrobial Peptides and Activities
Peking University
2006-2024
Beijing Forestry University
2023
Collaborative Innovation Center of Quantum Matter
2019
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics
2004-2009
Beijing City University
2007
High-temperature (HT) annealing effects on the evolution of strain in AlN films grown sapphire have been investigated. It is found that there a significant transition behavior from tensile to compressive before and after HT at an optimal temperature 1700 °C. Based microstructural analysis, it clarified will result (1) disappearance grains account for stress annealing, (2) generation new interface has little influence lattice constant upper/below this interface, (3) regular 8/9 arrangement...
Epitaxial growth of AlN films on c-sapphire using a multilayer structure has been investigated by metal–organic chemical vapor deposition adopting multiple alternation cycles low- and high-temperature (LT–HT) growth. It is found that the surface morphology crystal quality can be greatly improved three with X-ray diffraction ω-scan full width at half maximum values 311 548 arcsec for (0002) (10−12) peaks, respectively, which are induced three-dimensional (3D) two-dimensional (2D) modes caused...
AlGaN-based deep-ultraviolet light emitting diodes adopting an embedded delta-AlGaN thin layer with Al composition higher than that in conventional barriers have been investigated. The experimental result shows when the current is below 250 mA, maximum of external quantum efficiency and output power for proposed structure reach severally 1.38% 10.1 mW, which are enhanced significantly by 160% 197%, respectively, compared to ones, showing a tremendous improvement. We attribute inserted...
Enhancement of light extraction efficiency (LEE) AlGaN-based deep-ultraviolet (DUV) emitting diodes (LEDs) has been attempted by adopting Ag-nanodots/Al reflective electrodes on a highly transparent complex p-type layer. By thinning the p-GaN to several nm, DUV layer is achieved, making it meaningful for application composed Ag-nanodots and Al film allow most emitted upward be reflected back sapphire side. this approach, maximum output power external quantum DUV-LEDs with optimized Ag...
Abstract More and more research is focusing on the unmanned aerial vehicle (UAV) inspection of onshore wind/solar power stations; however, how to balance contradiction between detection accuracy efficiency still a challenge for domestic international researches. In this paper, sparse distribution targets in stations, YOLOv8 model used quickly extract information such as photovoltaic module contours key points wind turbine blades wide-angle image UAV. By connecting these series, fine route...
Current transport mechanism in Au∕Ni∕GaN Schottky diodes has been investigated using current-voltage characterization technique between 27 and 350°C. It is found that the ideality factor n of diode decreases with increasing temperature when lower than 230°C, then increases higher 230°C. The corresponding barrier height (SBH) all through range. Thermionic-emission model a Gaussian distribution SBHs thought to be responsible for electrical behavior at temperatures while...
A method of reducing threading dislocation (TD) density in AlN epilayers grown on sapphire substrate is reported. By introducing an buffer layer by a pulsed atomic-layer epitaxy method, TDs epitaxial films were greatly decreased. From transmission electron microscopic images, clear subinterface was observed between the and subsequently continuous epilayer. In vicinity subinterface, redirection, annihilation, termination observed. The increase lateral growth rate accounted for TD redirection...
Hot phosphor acid (H3PO4) etching is presented to form a roughened surface with dodecagonal pyramids on laser lift-off N face GaN grown by metalorganic chemical vapor deposition. A detailed analysis of time evolution morphology described as function temperature. The activation energy the H3PO4 process 1.25 eV, indicating reaction-limited scheme. And it found that oblique angle between facets and base plane increases temperature increases. Thermodynamics kinetics related factors formation...
The crystal quality evolution of AlN films <italic>via</italic> high-temperature (HT) annealing under nitrogen is investigated.
Carrier transport in AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) with the wavelength of 273 nm has been investigated by introducing polarization modulated electron blocking layer (EBL) that adopts an Al composition and thickness graded multiple quantum barriers (MQB) structure. The experimental result shows maximum output power external efficiency for proposed structure at current 250 mA are 9.6 mW 1.03% respectively, severally increasing 405% 249% compared to traditional...
The effect of high temperature annealing (HTA) on crystalline quality improvement h-BN films grown sapphire substrates has been investigated. It is found that BN using conventional molecular beam epitaxy disordered due to the growth below 1000 °C. By at a 1700 °C, thermodynamically stable could be obtained wafer scale, where diffusion atoms in as-grown film enhanced and structural defect density decreases. confirmed by x-ray diffraction, Raman scattering, atomic force microscopy...
Developing efficient active region structures with low sensitivity to threading dislocation density (TDD) is of great technical significance for AlGaN-based deep ultraviolet (DUV) light-emitting devices. Here, we propose an strategy by introducing bunching effect form self-assembled sidewall quantum wells (SQWs) much stronger carrier confinement, resulting in a significant enhancement internal efficiency (from 46% 59%) compared the commonly adopted multiple (MQWs) due lower TDD. As demo, DUV...
Abstract Utilizing the growth temperature controlled epitaxy, high quality GaN/In 0.15 Ga 0.85 N multiple quantum wells designed for intersubband transition (ISBT) as novel candidates in III-nitride infrared device applications have been experimentally realized first time. Photo-absorption originated from ISBT has successfully observed at regime covering 3–5 μm atmosphere window, where central absorption wavelength is modulated by adjusting well width. With increasing thickness, center wave...
Improving the contact characteristics of Ti/Al/Ni/Au on plasma etched n-AlGaN has been attempted by an active pretreatment, which can provide Si and N atoms to occupy possible metal vacancies. It is found that contacts both as-grown plasma-etched + pretreatment n-Al0.5Ga0.5N present truly Ohmic in nature, whereas samples without still remain rectifying. Surface atomic concentration analysis indicates etching induced or vacancies mostly act as acceptor-like states, leading a severe...
We report on a GaN/AlN quantum cascade detector operating in an extended spectral range going from the mid-infrared to visible wavelengths. This broadband detection is achieved thanks design of active wells supporting five bound-to-bound intersubband transitions. The photodetector exhibits broad signal between 4.1 μm and 550 nm. photocurrent persists up room temperature. calibrated responsivity at 77 K under irradiation through 45° angle polished facet amounts 7 μA/W wavelength 633 nm peaked 14 720
Abstract The high‐power white light emitting diode (LED) is packaged by GaN‐based blue LED chip with the size of 1 × mm 2 , YAG:Ce yellow fluorescer, epoxy and an effective heat sinking. wavelength emission blue‐shifts from 482 to 475 nm, while that fluorescer does not change in electroluminescence (EL) spectrum when injection current increases 5 200 mA. And correlated color temperature decreases 5300 4800 K. When mA, luminous power ( P e ) 13.8 mW, which about 10 times those normal (0.3 0.3...
Abstract AlGaN/GaN quantum structure is an excellent candidate for high speed infrared detectors based on intersubband transitions. However, fabrication of well suffers from polarization-induced internal electric field, which greatly limits the carrier vertical transport. In this article, a step proposed to attempt solving problem, in novel spacer barrier layer used balance field. As result, nearly flat band potential profile obtained layers wells and bound-to-quasi-continuum (B-to-QC) type...
Ga N ∕ Al x 1 − superlattices (SLs) with different period thicknesses tp were grown as interlayers between GaN and AlyGa1−yN epilayers. The effect of threading dislocations (TDs) blocking became more evident increasing tp. Transmission electron microscopy analysis shows that TDs are inclined to be bended in SLs terminated wells a result strain. X-ray diffraction measurement also validated played important role filter. resulted an abnormal decrease relaxation factors R(SLs)
The temperature dependence of the specific contact resistance in annealed Ti/Al/Ni/Au multilayers on (NH4)2Sx treated n-type GaN has been studied range from 25 to 600 °C by transmission line technique. It is found that resistivity ρc sample with solution for 5 min at 90 decreases increasing measuring temperature, while increases temperature. Excellent agreement “5 treated” can be obtained field emission model an average Schottky barrier height (SBH) ϕB=1.05 eV. Meanwhile, a...