A5010619352- GaN-based semiconductor devices and materials
- Ga2O3 and related materials
- Semiconductor materials and devices
- ZnO doping and properties
- Photocathodes and Microchannel Plates
- 2D Materials and Applications
- Semiconductor Quantum Structures and Devices
- Metal and Thin Film Mechanics
- Diamond and Carbon-based Materials Research
- Graphene research and applications
- Nanowire Synthesis and Applications
- Photonic and Optical Devices
- Photonic Crystals and Applications
- Silicon Nanostructures and Photoluminescence
- Silicon and Solar Cell Technologies
- Semiconductor materials and interfaces
- Silicon Carbide Semiconductor Technologies
- MXene and MAX Phase Materials
Lund University
2024-2025
Karlsruhe Institute of Technology
2023
Korea Polytechnic University
2014-2021
Korea Institute of Science and Technology
2021
Chinese University of Hong Kong
1995-1999
A DUV-LED with a graded superlattice electron blocking layer (GSL-EBL) is demonstrated to show improved carrier injection into the multi-quantum well region. The structures of modified EBLs are designed via simulation. simulation results behavior mechanism DUV-LEDs single EBL (S-EBL), (G-EBL), and GSL-EBL. variation in energy band diagram around region indicates that introduction GSL-EBL very effective enhancing injection. Besides, all emitting at 280 nm grown high temperature metal organic...
In this paper, a gradient electron blocking layer (GEBL) is introduced to improve efficiency of deep‐ultraviolet light‐emitting diodes (DUV‐LEDs). Various structures DUV‐LEDs are simulated determine the energy band diagram variation and carrier injection mechanism resulting from insertion GEBL. The simulation results show improved hole transport behavior in AlGaN multi quantum wells (MQWs). Especially, holes with increasing number GEBL steps, which lead enhancement internal (IQE). DUV‐LED...
In situ X-ray reciprocal space mapping was performed during the interval heating and cooling of InGaN/GaN quantum wells (QWs) grown via metal–organic vapor phase epitaxy (MOVPE). Our detailed in analysis enabled us to track changes peak intensities radial angular broadenings reflection. By simulating diffraction profiles recorded thermal cycle treatment, we demonstrate presence indium concentration distributions (ICDs) different QWs heterostructure (1. QW, bottom, 2. middle, 3. upper)....
We report deep ultraviolet (UVC) emitting core-shell-type AlGaN/AlN multiple quantum wells (MQWs) on the AlN nanorods which are prepared by catalyst/lithography free process. The MQWs grown a sapphire substrate polarity-selective epitaxy and etching (PSEE) using high-temperature metal organic chemical vapor deposition. through PSEE have low dislocation density because edge dislocations bent toward neighboring N-polar domains. three crystallographic orientations, final shape of structure is...
Herein, the effect of crystal quality AlN buffer layer on AlGaN/GaN/AlN double‐heterostructure high‐electron‐mobility transistor (DH‐HEMT) is investigated. The material GaN channel and AlGaN barriers, such as dislocation density interface roughness, deteriorates, 2D electron gas (2DEG) mobility decreases threading (TDD) increases. It also revealed that thickness Al mole fraction barrier are affected by strain variation depending TDD buffer. compressive responsible for 2DEG change affecting...
Abstract The present study investigated the Mg doping effect in gallium nitride (GaN) buffer layers (BLs) of AlGaN/GaN high-electron-mobility transistor (HEMT) structures grown on semi-insulating 4H-SiC substrates by metal organic chemical vapor deposition. When concentration was increased from 3 × 10 17 to 8 18 cm −3 , crystal quality slightly deteriorated, whereas electrical properties were significantly changed. leakage approximately 50 times 0.77 39.2 nA at −50 V with concentration....
Large area deep ultraviolet (DUV) light is generated by carbon nanotube (CNT) cold cathode electron beam (C-beam) irradiation on Al0.47Ga0.53N/Al0.56Ga0.44N multi quantum wells (MQWs) anode. We developed areal (EB) with CNT emitters. The emitters silicon wafer were deposited an of 188 mm2, and these vertically aligned had conical structures. optimized the C-beam conditions to effectively excite AlGaN MQWs. When MQWs excited using anode voltage 3 kV current 0.8 mA, DUV a wavelength 278.7 nm...
The AlGaN/AlN/GaN/AlN double‐heterostructure high‐electron mobility transistor (DH‐HEMT) on sapphire substrate is introduced, and its direct current (DC) radio frequency (RF) characteristics to the conventional GaN‐based single‐heterostructure HEMT (SH‐HEMT) SiC are compared. devices having two‐finger gate fabricated with width of 200 μm length 500 nm. DC performance DH‐HEMT shows a transconductance 0.233 S mm −1 maximum drain density 0.93 A , comparable that SH‐HEMT. There less‐pronounced...
Boron‐doped diamond layers are grown on freestanding heteroepitaxial substrates by microwave plasma chemical vapor deposition (MPCVD) to verify the high potential of large‐size as an ultimate semiconductor material. Due crystallinity and atomically flat surface morphology substrate, MPCVD‐grown boron‐doped layer exhibit excellent properties crystallinity, measured X‐ray diffraction atomic force microscopy. The temperature‐dependent Hall effect measurements conducted at temperature ranges...
The structural and chemical changes of the GaAs(110) surface induced by sequential processes UV/O3 exposure, HF etching, gas-phase polysulfide passivation were investigated x-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED), thermal desorption. Prior to any annealing, no samples showed LEED patterns, XPS indicated presence both As–S Ga–S bonds. When polysulfide-passivated was annealed 400 °C, a sharp oblique pattern started emerge, which accompanied desorption...
We investigated the growth behavior of GaN grown on AlN along with V/III ratio and pressure variation, found out lateral regime for fully coalesced channel layer AlN-based double-hetero structure high electron mobility transistor (HEMT). When increases decreases, compressive stress in increases, pit formation occurs to release stress. The HEMT was device fabricated an optimized layer. two-dimensional gas mobility, sheet density, resistance were 1480 cm2 V−1 s−1, 1.32 × 1013 cm−2, 319 Ω/sq.,...
Creating voids between thin films is a very effective method to improve film crystal quality. However, for AlN material systems, the layer growth, including voids, challenging because of high Al atom sticking coefficient. In this study, we demonstrated an template with many grown on nanorods made by polarity selective epitaxy and etching methods. We introduced low V/III ratio NH3 pulsed growth demonstrate high-quality coalesced templates in metal organic chemical vapor deposition reactor....
We investigated the correlation between crystal quality and two-dimensional electron gas (2DEG) mobility of an AlGaN/GaN high-electron-mobility transistor (HEMT) structure grown by metal-organic chemical vapor deposition. For with AlN nucleation layer at 1100 °C, 2DEG sheet carrier density were 1627 cm²/V·s 3.23 × 10¹³ cm⁻², respectively, room temperature. Further, it was confirmed that edge dislocation GaN buffer related to in HEMT.
In this study, a report is prepared on significantly low specific contact resistivity of alloyed and non‐alloyed ohmic contacts fabricated an as‐grown n + ‐GaN layer measured with the transfer length method. A ρ c = 8 × 10 −8 Ω cm 2 extracted for Ti/Al/Ni/Au, 4 −7 unannealed Ti/Pd/Au. To achieve these, highly doped N D 1.5 19 −3 used. The results are derived from study three different metal stacks, namely Ti/Al/Ni/Au (20 nm/300 nm/20 nm/400 nm), Ti/Pd/Au (2 nm/5 nm/200 Mo/Au (30 nm). studied...
Far-ultraviolet-C (UVC) light is an efficient and safe germicide because the wavelength band eradicates viruses but harmless to human cells. In this study, electron-beam-pumped AlGaN emitters have been introduced as alternative far-UVC emitting diodes which are limited by certain drawbacks, such low conductivity absorption of p-layer side emission due polarization at short wavelengths. We demonstrate a highly emitter using carbon nanotube-based cold cathode electron beam (C-beam). To...
The structural and chemical changes induced by the annealing of InP which has been exposed to gas-phase polysulfide, a known passivation method for reduction surface states InP, were investigated using in situ low-energy electron diffraction (LEED), thermal desorption spectrometry, x-ray photoelectron spectroscopy (XPS). A diffused (1×1) LEED pattern was observed on had ultraviolet/O3 followed etching with 1:30 HF solution. became sharper after polysulfide exposure subsequent annealing....