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Narrow-line InGaN/GaN green laser diode with high-order distributed-feedback surface grating
摘要： We demonstrate narrow-line green laser emission at 513.85 nm with a linewidth of 31 pm and side-mode suppression ratio of 36.9 dB, operating under continuous-wave injection at room temperature. A high-order (40th) distributed-feedback surface grating fabricated on multimode InGaN-based green laser diodes via a focused ion beam produces resolution-limited, single-mode lasing with an optical power of 14 mW, lasing threshold of 7.27 kA cm?2, and maximum slope efficiency of 0.32 W A?1. Our realization of narrow-line green laser diodes opens a pathway toward efficient optical communications, sensing, and atomic clocks.
关键词： InGaN/GaN,green laser diode,distributed-feedback,narrow-line,surface grating
更新于2025-11-28 14:23:57
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Structural, morphological, optical and electrical characterization of InGaN/GaN MQW structures for optoelectronic applications
摘要： InGaN/GaN Multiple Quantum Well (MQW) structures were grown on c-plane sapphire substrate using metal organic chemical vapour deposition technique by varying the MQW periods. The indium composition and thickness were estimated using high-resolution X-ray diffraction. InGaN well, GaN barriers and Indium composition were estimated as 3 nm, 18 nm and 16-18% using epitaxy smooth fit software. Reciprocal space mapping revealed that InGaN/GaN MQW samples were coherently strained. High-resolution transmission electron microscopy and scanning electron microscopy exhibit decrease in the surface roughness with increase in the number of InGaN/GaN MQW periods with respect to the number of defects comprising of threading dislocations and hexagonal V-pits. Self-organized In(Ga)N like nanostructures with spiral growth mechanism was also observed due to the low temperature growth of p-GaN layer. The photoluminescence spectra of the MQWs showed a red-shift when the number of QW periods was increased due to quantum confined stark effect. Hall Effect microscopy images confirmed good interface between the InGaN/GaN MQW structures. Atomic force microscopy and scanning electron microscopy exhibit decrease in the surface roughness measurement displayed good semiconducting behavior in the InGaN/GaN MQW structures. The carrier concentration values also emphasized adequate variations when number of periods was increased.
关键词： V-pits,InGaN,Photoluminescence,Multiple Quantum Well,nanostructures
更新于2025-11-21 11:18:25
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Influence of substrate and substrate temperature on the structural, optical and surface properties of InGaN thin films prepared by RFMS method
摘要： In this work, the pure InGaN thin films were grown using n-type and p-type silicon substrates at varying substrate temperatures using the sputtering method. The effects of substrate and substrate temperature on the structural, morphological and optical properties of the thin films grown were investigated. X-ray diffraction (XRD) analyzes of the obtained films illustrates crystal structures at C substrate temperature, the films were found to be hexagonal. Scanning electron microscopy (SEM) was used to investigate the shape, size and surface distribution of the particles formed on film surfaces. The reflection and optical band gap (Eg) of the films were investigated from the optical analyzes taken with the UV-VIS spectrophotometer. As a result of these analyzes, it has been reached that the substrate and substrate temperature have a great influence on the structural, morphological and optical properties of the films. The experimental findings obtained in the study are compared with the studies given in the literature and the similarities and differences are discussed.
关键词： InGaN growth,silicon substrate,thin films,sputtering technique,substrate temperature
更新于2025-09-23 15:23:52
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Stability, Electronic and Magnetic Properties of Rare Earth (Eu, Tm) Implanted InGaN
摘要： The electronic structure and magnetic behavior of InGaN:RE (RE = Eu, Tm) have been studied by using scalar relativistic full-potential linear augmented-plane-wave plus local orbital (FPLAPW + lo) calculations with LSDA+U approximation. Band structure and density of states are analyzed. It appears that the In-site is the preferred site for doping InGaN alloy with rares earth (Eu, Tm) from the formation energy. Our study reveals that these materials are semiconductors with a direct band gap of 1.2345 eV and 1.3657 eV for InGaN:Eu and InGaN:Tm respectively. The total energy of the FM phase is lower than the AFM total energy; this confirms the fact that the ground state at zero temperature is ferromagnetic. A small-induced magnetic moment on other nonmagnetic atoms (Ga, In, and N) and the total magnetic moment of these compounds is mainly due to RE-4f states.
关键词： InGaN alloy,Europium,DMS,Direct band gap,Thulium
更新于2025-09-23 15:22:29
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Electro-thermal modeling for InxGa1-xN/GaN based quantum well heterostructures
摘要： The joint effect of the heat transfer and the electronic properties in the InGaN/GaN based quantum well (QW) heterostructures has been investigated theoretically and numerically. One-dimensional Schr?dinger equation solver coupled with Poisson equation solver and Dual-phase-lagging (DPL) heat conduction solver has been developed. The numerical results suggest that the DPL heat conduction equations capture the microscale responses caused by the phonon-electron interaction. Both effects of the polarization charge and conduction band offset between the InGaN/GaN interfaces lead to the creation of the two-dimensional electron gas (2DEG) on the lower interface of the QW. It is found that the 2DEG density at the triangular quantum well increases with increasing Indium (In) composition. This increase is the same for the conduction band offset and the electron density. As a consequence, an increase of the heat dissipation and the temperature is observed at the lower interface of the quantum well.
关键词： Indium composition,Polarization charge,Nanoscale heat transfer,Dual-phase-lagging model,InGaN heterostructure
更新于2025-09-23 15:22:29
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V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate
摘要： InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.
关键词： V defects,Transmission electron microscopy (TEM),InGaN multi-quantum well (MQW),Threading dislocations (TDs)
更新于2025-09-23 15:22:29
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Advances in GaN Crystals and Their Applications
摘要： This special issue looks at the potential applications of GaN-based crystals in both ?elds of nano-electronics and optoelectronics. The contents will focus on the fabrication and characterization of GaN-based thin ?lms and nanostructures. It consists of six papers, indicating the current developments in GaN-related technology for high-ef?ciency sustainable electronic and optoelectronic devices, which include the role of the AlN layer in high-quality AlGaN/GaN heterostructures for advanced high-mobility electronic applications and simulation of GaN-based nanorod high-ef?ciency light-emitting diodes for optoelectronic applications. From the results, one can learn the information and experience available in the advanced fabrication of nanostructured GaN-based crystals for nano-electronic and optoelectronic devices.
关键词： MOSFET,AlN,InN,InGaN,AlGaN,LED,GaN
更新于2025-09-23 15:21:21
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Realization of ultra-high quality InGaN platelets to be used as relaxed templates for red microLEDs
摘要： In this work, arrays of predominantly relaxed InGaN platelets with indium contents of up to 18%, free from dislocations and offering a smooth top c-plane, are presented. The InGaN platelets are grown by metal-organic vapor phase epitaxy on a dome-like InGaN surface formed by chemical mechanical polishing of InGaN pyramids defined by six equivalent {1011} planes. The dome-like surface is flattened during growth, through the formation of bunched steps, which are terminated when reaching the inclined {1011} planes. The continued growth takes place on the flattened top c-plane with single bilayer surface steps initiated at the six corners between the c-plane and the inclined {1011} planes, leading to the formation of high quality InGaN layers. The top c-plane of the as-formed InGaN platelets can be used as a high quality template for red microLEDs.
关键词： selective area growth,InGaN,template,chemical mechanical polishing,vapor phase epitaxy,microLEDs
更新于2025-09-23 15:21:01
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High-quality nanodisk of InGaN/GaN MQWs fabricated by neutral-beam-etching and GaN regrowth: Towards directional micro-LED in top-down structure
摘要： A nanodisk array of blue InGaN/GaN multiple quantum wells was made using neutral beam etching (NBE) followed by GaN regrowth. The NBE-fabricated nanodisk presented a vertical and highly smooth sidewall surface where the InGaN well layers were easily distinguished even with a scanning electron microscope. A high interface quality without any voids or obvious defects was obtained between the nanodisk and the regrown-GaN layer. The nanodisk after regrowth presented a smaller blueshift of photoluminescence emission energy (12 meV) and a substantially higher and almost constant internal quantum efficiency of ~50% over three orders of magnitude of excitation laser power when compared to the nanodisk before regrowth. This study shows that the process of NBE nanodisk etching followed by GaN regrowth represents a promising step forward in the development of truncated cone-shaped directional micro-LEDs with a buried active region in a top-town structure.
关键词： Regrowth,InGaN/GaN MQWs,Directional micro-LED,Nanodisk,Neutral beam etching
更新于2025-09-23 15:21:01
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AIP Conference Proceedings [AIP Publishing 3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019) - Bikaner, India (14a??15 October 2019)] 3RD INTERNATIONAL CONFERENCE ON CONDENSED MATTER AND APPLIED PHYSICS (ICC-2019) - Effect of polarization field and Auger recombination on internal quantum efficiency of InGaN/GaN blue LED
摘要： InxGa1-x N/GaN blue LEDs faces significant efficiency droop issue. The causes of efficiency droop are Shockley Read Hall recombination (SRH), Auger recombination (AR), carrier delocalization and electron leakage. The SRH, Auger and electron leakage are functions of carrier concentration and temperature. InGaN/GaN superlattice has polarization electric field at interface. In this work we explore effect of polarization electric field on efficiency droop. It is shown that polarization field enhances Auger coefficient resulting in more droop in internal quantum efficiency of blue LED. Thus, for improvement in efficiency, polarization field required to be minimized which requires growth of the material in m- plane instead of c-plane.
关键词： efficiency droop,polarization electric field,Auger recombination,blue LED,InGaN/GaN
更新于2025-09-23 15:21:01