A5052188139- Photonic and Optical Devices
- GaN-based semiconductor devices and materials
- Semiconductor Quantum Structures and Devices
- Advanced Fiber Laser Technologies
- ZnO doping and properties
- Semiconductor Lasers and Optical Devices
- Ga2O3 and related materials
- Advanced Photonic Communication Systems
- Metal and Thin Film Mechanics
- Optical Network Technologies
- Semiconductor materials and devices
- Photorefractive and Nonlinear Optics
- Optical Coatings and Gratings
- Photonic Crystals and Applications
- Nanowire Synthesis and Applications
- Acoustic Wave Resonator Technologies
- Advanced Fiber Optic Sensors
- Advanced Semiconductor Detectors and Materials
- Advanced Optical Sensing Technologies
- Spectroscopy and Laser Applications
- Photocathodes and Microchannel Plates
- Mechanical and Optical Resonators
- Semiconductor materials and interfaces
- Plasmonic and Surface Plasmon Research
- Plasma Diagnostics and Applications
Tsinghua University
2016-2025
South China University of Technology
2025
Guangzhou University
2025
Peking University
2024
Institute of Physics
2023
National Engineering Research Center for Information Technology in Agriculture
2021-2022
University of California, Berkeley
2021
State Key Laboratory on Integrated Optoelectronics
2004-2018
University of California, Los Angeles
2008-2009
Development of planar-integrated microresonators with high quality factors (Q's) is crucial for nonlinear photonics in a robust chip. Compared silicon and nitride, aluminum nitride (AlN) features intrinsic quadratic cubic susceptibilities as well an enormous band gap (∼6.2 eV), making it ideal optical interactions. However, sputtered polycrystalline AlN susceptible to scattering defect-related absorption losses, thereby inducing limited Q-factors. Here, we demonstrate single-crystalline...
Abstract Gallium nitride (GaN) as a wide bandgap material is widely used in solid‐state lighting. Thanks to its high nonlinearity and refractive index contrast, GaN‐on‐insulator (GaNOI) also promising platform for nonlinear optical applications. Despite intriguing proprieties, applications of GaN are rarely studied owing the relatively loss waveguides (typically ≈2 dB cm −1 ). In this paper, GaNOI microresonators with intrinsic quality factor over 2.5 million reported, corresponding an 0.17...
The data rate of a visible light communication (VLC) system is basically determined by the electrical-to-optical (E-O) bandwidth its light-emitting diode (LED) source. In order to break through intrinsic limitation carrier recombination on E-O in conventional c-plane LEDs based InGaN quantum wells, blue micro-LED with an active region nano-structured wetting layer designed, fabricated, and packaged realize high-speed VLC system. can reach up 1.3 GHz. Based this micro-LED, we demonstrated 2...
Significance As high-power devices approach nanoscale, interface thermal conductance (ITC) becomes a bottleneck to govern the device performance, which is dominated by phonons. In order gain insights into engineering ITC, here we measure local phonons across AlN/Si and AlN/Al interfaces using atomically resolved vibrational electron energy-loss spectroscopy. We find that dominant types of for ITC are very different in these two systems demonstrate ability correlate measured with at atomic...
Ultra-small micro-LEDs are essential for next-generation display technology. However, below 5 μm have been seldom reported. In this work, we demonstrate InGaN-based blue and green from 1 to 20 by using laser direct writing lithography. The 1-μm show a peak external quantum efficiency of 13.02%, which is 9.57% ones. By characterizing the size-dependent simply assuming that variety dominantly determined dry-etching induced dead zone, deduce zone sizes carrier injection at edge chips 0.18 0.15...
Novel back-illuminated modified uni-traveling-carrier photodiodes (MUTC-PDs) with wide bandwidth and high saturation power are demonstrated. The effect of cliff layer doping on the electric field distribution is investigated to achieve fast carrier transport. MUTC-PDs miniaturized device diameter low contact resistance fabricated improve RC-limited bandwidth. Meanwhile, inductive peaking implemented further extend PDs 3-µm 3.6-µm-diameter exhibit a ultrawide 230 GHz 200 GHz, together -4.94...
Two light-emitting diode samples are grown with InGaN and GaN underlying layers beneath the multiple quantum wells (MQWs), respectively. By measuring carrier lifetime as a function of photon energy, it is found that MQW layer has higher degree localization. Comparison between external efficiency injection current these two reveals droop at small attributed to delocalization carriers, while further due mostly leakage demonstrated through temperature-dependent electroluminescence measurements.
Wurtzite aluminum nitride (AlN) is known to exhibit six Raman-active optic phonons, making it appealing for Raman lasing. Here, we demonstrate continuous-wave lasers with a low threshold and high slope efficiency in quality factor AlN-on-sapphire microrings. Stokes radiations around 1.7–1.8 μm cascaded operation into 1.9–2.0 μm are identified telecom pump. Two types of lights distinct shifts polarizations recorded via selective excitation corresponding accordance the selection rules AlN. The...
We demonstrate aluminum nitride (AlN) on sapphire as a novel platform for integrated optics. High-confinement AlN microring resonators are realized by adopting partially etched (pedestal) waveguide to relax the required etching selectivity exact pattern transfer. A wide taper is employed at chip end facets ensure low fiber-to-chip coupling loss of ~2.8 dB/facet both transverse-electric (TE) and transverse-magnetic (TM) modes. Furthermore, intrinsic quality factors (Qint) recorded with...
Abstract Micro‐LEDs are regarded as ideal light sources for next‐generation display and high‐speed visible‐light communication (VLC). However, the conventional micro‐LEDs based on InGaN quantum well (QW) active region suffer from a low efficiency under small injection (below 1 A cm −2 ) due to size‐dependent effect limited 3 dB bandwidth (hundreds of MHz) quantum‐confined Stark effect. Here, dots (QDs) proposed address these challenges their strong localization low‐strain features. Green QDs...
A novel thin-film lithium niobate (TFLN) electro-optic modulator is proposed and demonstrated. LiNbO3-silica hybrid waveguide adopted to maintain low optical loss for an electrode spacing as narrow 3 µm, resulting in a half-wave-voltage length product of only 1.7 V·cm. Capacitively loaded traveling-wave electrodes are employed reduce the microwave loss, while quartz substrate used place silicon achieve velocity matching. The fabricated TFLN with 5-mm-long modulation region exhibits half-wave...
A carrier rate model taking delocalization into account is presented to analyze current dependent internal quantum efficiency of InGaN based light-emitting diodes (LEDs). By fitting normalized experimental efficiency-current curves, both injection and radiative recombination depending on can be obtained. Based the results from two LED samples with without interlayer beneath active regions 5 wells (QWs), leakage are believed lead droop effect under considerable even larger injection,...
One of the major challenges for application GaN-based light emitting diodes (LEDs) in solid-state lighting lies low output power (LOP). Embedding nanostructures LEDs has attracted considerable interest because they may improve LOP efficiently. Recent advances derived from monolayer colloidal crystal (MCC) have made remarkable progress enhancing performance LEDs. In this review, current state art field is highlighted with an emphasis on fabrication ordered using large-area, high-quality MCCs...
Stranski–Krastanov (SK) growth mode is widely adopted for the self-assembled of semiconductor quantum dots (QDs), wherein a relatively large critical thickness essential and thick wetting layer (WL) formed beneath QD layer. In this paper, we report metal organic vapor phase epitaxy green InGaN QDs, employing interruption method to decrease improve morphology QDs. The QDs exhibit similar photoluminescence properties with those grown by conventional SK mode, implying existence WL. We...
Semiconductor devices capable of generating a vortex beam with specific orbital angular momentum (OAM) order are highly attractive for applications ranging from nanoparticle manipulation, imaging and microscopy to fiber quantum communications. In this work, an electrically pumped integrated OAM emitter operating at telecom wavelengths is fabricated by monolithically integrating optical distributed feedback laser on the same InGaAsP/InP epitaxial wafer. A single-step dry-etching process...
Efficiency droop is currently one of the most popular research problems for GaN-based light-emitting diodes (LEDs). In this work, a differential carrier lifetime measurement system optimized to accurately determine lifetimes (τ) blue and green LEDs under different injection current (I). By fitting τ-I curves efficiency according ABC rate equation model, impact Auger recombination leakage on can be characterized simultaneously. For samples used in it found that experimental cannot described...
Novel back-illuminated modified uni-traveling- carrier photodiodes (MUTC-PDs) are reported to demonstrate wide bandwidth and high output power performance at D-band (110–170 GHz) regime. A comprehensive design model is employed predict tune the frequency response by incorporating coplanar waveguides (CPWs) with different inductive peaking effects. As a demonstration, 4.5-μm-diameter two types of CPWs fabricated exhibit profiles. Both PDs 3-dB over 150 GHz measured responses in excellent...
Novel evanescently coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) employing a thick multi-layer coupling are reported. To improve the optical-to-electrical (O/E) conversion efficiency, with gradually increased refractive index from bottom layer to absorption is utilized. The profile facilitates upward transmission of incident light into region, thereby enhancing evanescent efficiency. Meanwhile, waveguide, total thickness 1.75 µm, expands mode field diameter,...
Abstract The rapid development of internet things (IoT) urgently needs edge miniaturized computing devices with high efficiency and low-power consumption. In-sensor has emerged as a promising technology to enable in-situ data processing within the sensor array. Here, we report an optoelectronic array for in-sensor by integrating photodiodes (PDs) resistive random-access memories (RRAMs). PD-RRAM unit cell exhibits reconfigurable output photo-responsivity programming RRAMs into different...
Optical neural networks are at the forefront of computational innovation, utilizing photons as primary carriers information and employing optical components for computation. However, fundamental nonlinear device in is barely satisfied because its high energy threshold poor reconfigurability. This paper proposes demonstrates an sigmoid-type computation mode Vertical-Cavity Surface-Emitting Lasers (VCSELs) biased beneath threshold. The programmable by simply adjusting injection current....