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Investigation of yellow luminescence intensity of N-polar unintentionally doped GaN

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Chinese Physics B 2011年第3期20卷 455-459页

作者：杜大超张进成欧新秀王昊陈珂薛军帅许晟瑞郝跃 Key Laboratory of Wide Band-Gap Semiconductors and Devices School of Microelectronics Xidian University

This paper reports that the yellow luminescence intensity of N-polar GaN Epi-layers is much lower than that of Ga-polar ones due to the inverse polarity, and reduces drastically in the N-polar unintentionally-doped GaN after etching in KOH solution. The ratio of yellow luminescence intensity to band-edge emission intensity decreases sharply with the etching time. The full width at half maximum of x-ray diffraction of （10-12） plane falls sharply after etching, and the surface morphology characterized by scanning electron microscope shows a rough surface that changes with the etching time. The mechanism for the generation of the yellow luminescence are explained in details.

关键词： N-polar GaN yellow luminescence KOH etching

Effect of the V/Ⅲ ratio during buffer layer growth on the yellow and blue luminescence in undoped GaN epilayer

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Science China(Physics,Mechanics & Astronomy) 2013年第9期56卷 1694-1698页

作者： CHAI XuZhao ZHANG Yun LIU Bin XIE ZiLi HAN Ping YE JianDong HU LiQun XIU XiangQian ZHANG Rong ZHENG YouDou School of Electronic Science and Engineering Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic MaterialsNational Laboratory of Solid State MicrostructureNanjing University

Effect of the V/III ratio during buffer layer growth on the yellow and blue luminescence in undoped GaN epilayer has been studied by means of photoluminescence spectroscopy and high resolution X-ray *** is found that the densities of screw and edge threading dislocations increase with the V/III ratio of the buffer layer,and the intensities of the yellow luminescence(YL) and blue luminescence(BL) emissions also increase ***,the density ratio of the edge threading dislocation to the screw threading dislocation remains invariant,as well as the intensity ratio of YL emission to BL *** can be concluded from these phenomena that the edge threading dislocation and screw threading dislocation can enhance the YL and BL emissions,respectively.

关键词： yellow luminescence blue luminescence V/Ⅲ ratio

Nanocrystalline rare earth fluorides doped with Pr^(3+) ions

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Journal of Rare Earths 2016年第8期34卷 802-807页

作者： Marcin Runowski Stefan Lis Department of Rare Earths Faculty of Chemistry Adam Mickiewicz University

Praseodymium（III） doped CeF3, CeF3：Gd, LaF3, GdF3 and YF3 inorganic fluorides were precipitated in an aqueous, sur- factant-free solution, using NH4F as a source of fluoride ions. The as-prepared products were subjected to a hydrothermal treatment, which led to the formation of crystalline nanoluminophores, composed of spherical （30 nm） and elongated （40-200 nm） nanos- tructures. Due to the presence of Pr3＋ ions, the synthesized nanomaterials showed yellow luminescence under a blue light irradiation. The nanoluminophore based on the YF3 host revealed the most promising spectroscopic properties, i.e., bright and intensive emission, hence it was investigated in detail. The photophysical properties of the nanomaterials obtained were studied by powder X-ray diffrac- tion （XRD）, transmission electron microscopy （TEM） and spectrofluorometry, i.e., measurements of excitation/emission spectra and luminescence decay curves.

关键词： yellow luminescence lanthanide fluorides Pr3+ doping nanocrystals hydrothermal post-treatment Ce3+ quenching rare earths

Highly regular rosette-shaped cathodoluminescence in GaN selfassembled nanodisks and nanorods

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Nano Research 2020年第9期13卷 2500-2505页

作者： Bijun Zhao Mark Nicolas Lockrey Naiyin Wang Philippe Caroffu Xiaoming Yuan Li Li JenniferWong-Leung Hark Hoe Tan Chennupati Jagadish Departm ent of Electronic Materials Engineering Research School of PhysicsThe Australian National UniversityCanberra 0200ACTAustralia Australian National Fabrication Facility Research School of PhysicsThe Australian National UniversityCanberra 0200ACTAustralia Hunan Key Laboratory for Supermicrostructure and Ultrafast Process School of Physics and ElectronicsCentral South University932 South Lushan RoadChangsha 410083China ARC Centre of Excellence for Transformative Meta-O ptical Systems Research School of PhysicsThe Australian National UniversityCanberra 0200ACTAustralia

Self-assembled GaN nanorods were grown by metal-organic chemical vapor deposition.A highly regular rosette-shaped cathodoluminescence pattern in the GaN nanorods is observed,where its origin is helpful to deepen the understanding of GaN nanorod *** pattern forms at the very early stages of nanorod growth,which consists of yellow luminescence at the edges and the non-luminous region at six vertices of the *** clarify its origin,we carried out detailed cathodoluminescence studies,electron microscopy studies and nanoscale secondary ion mass spectrometry at both the nanorod surface and *** found the pattern is not related to optical resonance modes or polarity inversion,which are commonly reported in GaN *** chemical composition and strain analysis,we found higher carbon and nitrogen cluster concentration and large compressive strain at the pattern *** pattern formation may relate to facet preferential distribution of non-radiative recombination centers related to excess carbon/*** work provides an insight into strain distribution and defect-related emission in GaN nanorod,which is critical for future optoelectronic applications.

关键词： metalorganic chemical vapor deposition(MOCVD) GaN nanorod cathodoluminescence yellow luminescence non-radiative recombination

luminescence of a GaN grain with a nonpolar and semipolar plane in relation to microstructural characterization

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Chinese Physics B 2012年第6期21卷 520-524页

作者：周小伟许晟瑞张进成党纪源吕玲郝跃郭立新 Key Laboratory of Wide Band-Gap Semiconductor Technology School of MicroelectronicsXidian University School of Science Xidian University Flight Automatic Control Research Institute AVIC

We report on the growth of the high-quality GaN grain on a r-plane sapphire substrate by using a self-organized SiN interlayer as a selective growth mask. Transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy are used to reveal the effect of SiN on the overgrown a-plane GaN growth. The SiN layer effectively terminates the propagation of the threading dislocation and basal plane stacking faults during a-plane GaN regrowth through the interlayer, resulting in the window region shrinking from a rectangle to a ＂black hole＂. Furthermore, strong yellow luminescence （YL） in the nonpolar plane and very weak YL in the semipolar plane on the GaN grain is revealed by cathodoluminescence, suggesting that C-involved defects are responsible for the YL.

关键词： nonpolar semipolar GaN yellow luminescence

Influence of growth rate on the carbon contamination and luminescence of GaN grown on silicon

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Journal of Semiconductors 2015年第9期36卷 26-29页

作者：毛清华刘军林吴小明张建立熊传兵莫春兰张萌江风益 National Engineering Technology Research Center for LED on Si Substrate Nanchang University

The unintentional carbon doping concentration of GaN films grown by low pressure metal organic chemical vapor deposition （LP-MOCVD） depends strongly on the growth rate. The concentration of carbon is varied from 2.9 × 1017 to 5.7 × 10^18 cm-3 when the growth rate increases from 2.0 to 7.2 μm/h, as detected by secondary ion mass spectroscopy. It is shown that the presence of N vacancies give rises to high carbon concentration. We show that a reduction of the carbon concentration by one order of magnitude compared to the regular sample with nearly same growth rate can be achieved by operating at an extremely high NH3 partial pressure during growth. The intensity ratios of yellow and blue luminescence to band edge luminescence in the samples are found to depend significantly on carbon concentration. The present results demonstrate direct and quantitative evidence that the carbon related defects are the origin of yellow and blue luminescence.

关键词： GaN optoelectronic devices carbon contamination high growth rate yellow luminescence