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Physical properties of RF magnetron sputtered GaN/n-Si thin film: impacts of RF power
摘要： GaN thin film was successfully produced on n-Si(100) substrate by RF magnetron sputter under different RF power. Experimental measurement techniques such as UV/Vis spectroscopy, field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and Micro-Raman Spectroscopy were used to research effects of Radio Frequency power on physical properties of produced thin film. It has been found that produced thin film was polycrystalline structure with (100) and (110) planes of hexagonal GaN from X-ray diffraction measurement result. It also proved that increasing RF power gives rise to deterioration in crystal quality of GaN thin film. Reason of this deterioration was discussed. It has been achieved that increasing RF power has resulted in decreasing optical band gap energy of GaN thin film. Reasons for these changes in optical band gap energy were explained. It was seen that some thin films were grown as layer-plus-island mode (Stranski–Krastanov growth mode) and others were grown as layer-by-layer growth mode (Frank van der Merwe mode) from AFM analysis. It has been found that increasing RF power has resulted in improvement of surface morphology of thin film from field emission scanning electron microscopy analysis. However, reaching RF power to 125 W leads to start to deteriorate of surface of GaN thin film. The reasons for this have been discussed. E1(TO) transverse optical phonon mode of hexagonal GaN with different intensity was detected from Micro-Raman Spectroscopy measurement. The reasons for this difference have been discussed. It was concluded that RF power has played a significant role in growing high quality GaN thin film. Morphological, structural, and optical properties of GaN thin film were enhanced by controlling RF power, making them a potential candidate for LED, solar cell, diode application.
关键词： Thin film,III-nitride,RF magnetron sputter,Semiconductor,GaN
更新于2025-11-14 15:25:21
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Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator
摘要： Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 μA, and a maximum power of 167 μW at a load resistance of 5 M?. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles.
关键词： flexible,piezoelectric generators,thin film,III-nitride,self-powered system,biocompatible
更新于2025-09-23 15:23:52
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[ACM Press the 2017 International Conference - Osaka, Japan (2017.10.22-2017.10.24)] Proceedings of the 2017 International Conference on Telecommunications and Communication Engineering - ICTCE '17 - Design of a four-branch optical power splitter using III-nitride semiconductors
摘要： This paper reports the design of a four-branch optical power splitter using MMI structure and taper output branches in III-nitride semiconductors. The numerical experimental is conducted using the 3D FD-BPM method. The results show that the optical power splitter has an excess loss of 0.27 dB and imbalance of 0.12 dB. It is also shown that the proposed design can be realized for C band range. This result opens the opportunity for the future device using this technology.
关键词： FD-BPM method,MMI structure,optical power splitter,III-nitride
更新于2025-09-23 15:23:52
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Selective Area Deposition of Hot Filament CVD Diamond on 100 mm MOCVD Grown AlGaN/GaN Wafers
摘要： A new technique is reported for selective growth of polycrystalline diamond by hot filament chemical vapor deposition (HFCVD) on AlGaN/GaN-on-Si (111) wafers without degradation of the underlying layers. Selective diamond seeding is accomplished by dispersing nano-diamond seeds in photoresist and patterned lithographically prior to HFCVD growth. A thin layer of plasma enhanced CVD SiNx, deposited prior to seeding and diamond deposition, was found to be essential to protect the AlGaN/GaN wafer. Methane concentration of 3.0% was used to achieve increased diamond growth rate and faster surface coverage. Excellent selectivity and minimal AlGaN surface damage were achieved due to the protective layer and faster surface coverage with increased methane concentration. Damage mitigation was confirmed by comparison of atomic force microscopy, x-ray diffraction, and Raman spectroscopy, each conducted before and after diamond deposition, and by SEM images of the final structures.
关键词： 2DEG,Reciprocal space mapping,III-Nitride,SiNx,Selective area deposition,CVD diamond,Photolithography,GaN decomposition
更新于2025-09-23 15:22:29
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Structural and electronic properties of III-nitride nanoribbons
摘要： The structural and electronic properties of group III-nitride nanoribbons have been systematically investigated using density functional theory calculations. We computed the edge stresses and edge moduli for III-nitride nanoribbons with a variety of widths and edge terminations, including bare, fully as well as partially hydrogen-passivated edges. In addition, fluorine-passivated zigzag-terminated nanoribbons were also investigated. Our results show that all edges of III-nitride nanoribbons are subjected to compressive stresses. The magnitude of edge stresses strongly depends on the edge terminations. Compressive stress states of nanoribbon edges result in drastically different edge distortions and edge elastic moduli, depending again on the edge configurations. Finally, the electronic band structures are calculated for all zigzag-terminated nanoribbons. We found only fully-passivated nanoribbons are semiconductors with indirect bandgaps. These results suggest that edge terminations significantly affect the edge elastic properties as well as the electronic properties of group III-nitride nanoribbons and their applications.
关键词： edge stresses,III-nitride nanoribbons,edge moduli,electronic band structures,density functional theory
更新于2025-09-23 15:21:01
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Thermal Design Considerations for III-N Vertical-Cavity Surface-Emitting Lasers Using Electro-Opto-Thermal Numerical Simulations
摘要： III-N VCSELs undergo severe self-heating which limits the output optical power. This makes thermal management a critical design consideration. The three most common VCSEL structures (hybrid VCSELs, flip-chip VCSELs and ELOG VCSELs) have been studied using advanced self-consistent electro-opto-thermal numerical simulations. The key geometric and material parameters affecting the thermal resistance of these devices have been identified. Our simulations suggest that some of the proposed solutions and design modifications can increase the maximum optical output power by as much 100%. This manuscript also describes the correct method of using numerical simulation in device design—to predict trends and isolate the key factors affecting device performance.
关键词： electro-opto-thermal simulation,thermal resistance,VCSEL,III-Nitride,laser diode,device modeling
更新于2025-09-19 17:13:59
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Development of microLED
摘要： This perspective provides an overview of early developments, current status, and remaining challenges of microLED (lLED) technology, which was first reported in Applied Physics Letters in 2000 [S. X. Jin, J. Li, J. Z. Li, J. Y. Lin and H. X. Jiang, "GaN Microdisk Light Emitting Diodes," Appl. Phys. Lett. 76, 631 (2000)]. Today, microLED is recognized as the ultimate display technology and is one of the fastest-growing technologies in the world as technology giants utilize it on a wide range of products from large flat panel displays and televisions, wearable displays, and virtual reality displays to light sources for the neural interface and optogenetics. It is anticipated that the collective R&D efforts worldwide will bring microLED products not only to the mass consumer electronic markets but also to serve the society on the broadest scale by encompassing sectors in medical/health, energy, transportation, communications, and entertainment.
关键词： microLED,optogenetics,display technology,III-nitride,neural interface
更新于2025-09-19 17:13:59
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Band engineering of III-nitride-based deep-ultraviolet light-emitting diodes: A review
摘要： III-nitride deep ultraviolet (DUV) light-emitting diodes (LEDs) are identified as the promising candidate for energy-efficient, environment-friendly and robust UV lighting source in the application of water/air purification, sterilization, and bio-sensing. However, the state-of-art DUV LED performance is far from satisfaction for commercialization owing to its low internal quantum efficiency, large current leakage and efficiency droop at high current injection, etc. Extensive efforts have been devoted to properly designing the band structures of such luminescent devices to enhance their output power. In this review, we summarize the recent progress on various energy band designs and engineering of DUV LEDs, with particular of interest is paid on the various approaches in band engineering of the electron-blocking layer, quantum well, quantum barrier and the implementation of many novel structures such as tunnel junctions, ultrathin quantum heterostructures to enhance their efficiency. Those inspirational approaches pave the way towards the next generation of greener and efficient UV sources for practical applications.
关键词： Quantum well,Quantum barrier,Deep ultraviolet light-emitting diode,Ultrathin quantum heterostructures,Band engineering,Electron-blocking layer,Tunnel junctions,III-nitride
更新于2025-09-19 17:13:59
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Evidence of trap-assisted Auger recombination in low radiative efficiency MBE-grown III-nitride LEDs
摘要： By studying low radiative e?ciency blue III-nitride light emitting diodes (LEDs), we ?nd that the ABC model of recombination commonly used for understanding e?ciency behavior in LEDs is insu?cient and that additional e?ects should be taken into account. We propose a modi?cation to the standard recombination model by incorporating a bimolecular nonradiative term. The modi?ed model is shown to be in much better agreement with the radiative e?ciency data and to be more consistent than the conventional model with very short carrier lifetimes measured by time-resolved photoluminescence in similar, low radiative e?ciency material. We present experimental evidence that a hot carrier-generating process is occurring within these devices, in the form of measurements of forward photocurrent under forward bias. The forward photocurrent, due to hot carrier generation in the active region, is present despite the lack of any “e?ciency droop”—the usual signature of band-to-band Auger recombination in high-quality III-nitride LEDs. Hot carrier generation in the absence of band-to-band Auger recombination implies that some other source of hot carriers exists within these low radiative e?ciency devices, such as trap-assisted Auger recombination.
关键词： hot carrier generation,III-nitride LEDs,ABC model,trap-assisted Auger recombination,radiative efficiency
更新于2025-09-12 10:27:22
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Electron‐Beam‐Driven III‐Nitride Plasmonic Nanolasers in the Deep‐UV and Visible Region
摘要： Plasmonic nanolasers based on wide bandgap semiconductors are presently attracting immense research interests due to the breaking in light diffraction limit and subwavelength mode operation with fast dynamics. However, these plasmonic nanolasers have so far been mostly realized in the visible light ranges, or most are still under optical excitation pumping. In this work, III-nitride-based plasmonic nanolasers emitting from the green to the deep-ultraviolet (UV) region by energetic electron beam injection are reported, and a threshold as low as 8 kW cm?2 is achieved. A fast decay time as short as 123 ps is collected, indicating a strong coupling between excitons and surface plasmon. Both the spatial and temporal coherences are observed, which provide a solid evidence for exciton-plasmon coupled polariton lasing. Consequently, the achievements in III-nitride-based plasmonic nanolaser devices represent a significant step toward practical applications for biological technology, computing systems, and on-chip optical communication.
关键词： plasmonic nanolasers,electron-beam-driven,deep-ultraviolet region,III-nitride
更新于2025-09-11 14:15:04