• Title/Summary/Keyword: cathodoluminescence(CL)

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Introduction to Cathodoluminescence Spectroscopy Using Scanning Transmission Electron Microscopy (주사 투과 전자현미경을 활용한 음극형광 분석법)

  • Sung-Dae Kim
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.4
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    • pp.326-331
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    • 2023
  • The utilization of scanning transmission electron microscopy (STEM) in conjunction with cathodoluminescence (CL) has emerged as a valuable tool for the investigation of material optical properties. In recent years, this technique has facilitated significant advancements in the fields of plasmonics and quantum emitters by surpassing prior technical restrictions. The review commences by providing an outline of the diverse STEM-CL operating modes and technical aspects of the instrumentation. The review explains the fundamental physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments for different types of excitations. Additionally, the review compares STEM-CL to other related techniques such as scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy.

Protective Metal Oxide Coatings on Zinc-sulfide-based Phosphors and their Cathodoluminescence Properties

  • Oh, Sung-Il;Lee, Hyo-Sung;Kim, Kwang-Bok;Kang, Jun-Gill
    • Bulletin of the Korean Chemical Society
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    • v.31 no.12
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    • pp.3723-3729
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    • 2010
  • We investigated the high-excitation voltage cathodoluminescence (CL) performance of blue light-emitting (ZnS:Ag,Al,Cl) and green light-emitting (ZnS:Cu,Al) phosphors coated with metal oxides ($SiO_2$, $Al_2O_3$, and MgO). Hydrolysis of the metal oxide precursors tetraethoxysilane, aluminum isopropoxide, and magnesium nitrate, with subsequent heat annealing at $400^{\circ}C$, produced $SiO_2$ nanoparticles, an $Al_2O_3$ thin film, and MgO scale-type film, respectively, on the surface of the phosphors. Effects of the phosphor surface coatings on CL intensities and aging behavior of the phosphors were assessed using an accelerating voltage of 12 kV. The MgO thick film coverage exhibited less reduction in initial CL intensity and was most effective in improving aging degradation. Phosphors treated with a low concentration of magnesium nitrate maintained their initial CL intensities without aging degradation for 2000 s. In contrast, the $SiO_2$ and the $Al_2O_3$ coverages were ineffective in improving aging degradation.

Enhanced Cathodoluminescence of KOH-treated InGaN/GaN LEDs with Deep Nano-Hole Arrays

  • Doan, Manh-Ha;Lee, Jaejin
    • Journal of the Optical Society of Korea
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    • v.18 no.3
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    • pp.283-287
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    • 2014
  • Square lattice nano-hole arrays with diameters and periodicities of 200 and 500 nm, respectively, are fabricated on InGaN/GaN blue light emitting diodes (LEDs) using electron-beam lithography and inductively coupled plasma reactive ion etching processes. Cathodoluminescence (CL) investigations show that light emission intensity from the LEDs with the nano-hole arrays is enhanced compared to that from the planar sample. The CL intensity enhancement factor decreases when the nano-holes penetrate into the multiple quantum wells (MQWs) due to the plasma-induced damage and the residues. Wet chemical treatment using KOH solution is found to be an effective method for light extraction from the nano-patterned LEDs, especially, when the nano-holes penetrate into the MQWs. About 4-fold CL intensity enhancement factor is achieved by the KOH treatments after the dry etching for the sample with a 250-nm deep nano-hole array.

A Study on the Cathodoluminescence and Structure of Thin Film $ZnGa_2O_4:Mn$ Oxide Phosphor (박막형 $ZnGa_2O_4:Mn$ 산화물 형광체의 음극선루미느센스와 구조적 특성에 관한 연구)

  • Kim, Joo-Han;Holloway Paul H.
    • Journal of the Korean Vacuum Society
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    • v.15 no.5
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    • pp.541-546
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    • 2006
  • In this study we have investigated cathodoluminescence (CL) and structural properties of thin film $ZnGa_2O_4:Mn$ oxide phosphor by using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), photoluminescence (PL), and cathodoluminescence. PL emission peaked at 506 nm was observed from the $ZnGa_2O_4:Mn$ phosphor target and it was attributed to the $^4T_1-^6A_1$ transition in $Mn^{2+}$ ion. The color coordinates of the emission were x = 0.09 and y = 0.67. The $ZnGa_2O_4:Mn$ films showed the excitation spectrum peaked at 294 nm by $Mn^{2+}$ ion absorption. It was found that the higher intensity of CL emission at 505 nm appears to result from the denser and closely-packed structure in $ZnGa_2O_4:Mn$ phosphor films deposited at lower pressures. The CL intensity did not show any systematic dependence on film surface roughness.

Synthesis of ZnO:Zn Phosphors with Reducing Atmosphere and Their Luminescence Properties (환원분이기에 따른 ZnO:Zn 형광체의 합성 및 그 형광 특성)

  • 김봉철;백종봉;한윤수;이남양;이병교
    • Journal of the Korean Ceramic Society
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    • v.37 no.1
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    • pp.1-5
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    • 2000
  • Cathodoluminescence(CL) properties of ZnO:Zn green phosphor were investigated. ZnO:Zn phosphor was synthesized by varying reducing agents and firing temperatures. ZnS, charcoal and 5% H2 gas mixed with 95% N2 gas(5H2-95N2) were used as the reducing agent and atmosphere. The highest CL intensity of ZnO:Zn phosphor was observed under the condition of 5H2-95N2 atmosphere and firing temperature of 90$0^{\circ}C$ for 1h. Charocal and ZnO as reducing agents in the syntehsis of ZnO:Zn phosphor exhibited about 60% and 40%, respectively, of the CL intensity obtained with 5H2-95N2 atmosphere.

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Cathodoluminescence Study of Diamond Films Grown by Cyclic Deposition Method (Cyclic 증착방법에 의해성장된 다이아몬드 박막의 cathodoluminescence 특성에 관한 연구)

  • Seo, Soo-Hyung;Shin, Wan-Chul;Park, Jin-Seok
    • Proceedings of the KIEE Conference
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    • 2001.11a
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    • pp.12-15
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    • 2001
  • Polycrystalline diamond films are deposited by cyclic method. modulating the $H_2$ Plasma and $CH_4+H_2$ plasma during the growth step. Diamond quality is evaluated by FWHM and $I_D/I_G$ ratio obtained from Raman spectroscopic analysis. Structural defects and impurities generated during the growth step are characterized by cathodoluminescence, and the variations between band-A(430 nm) line and nitrogen-related(578 nm) line are investigated as a function of $T_E/T_G$. Furthermore, the correlations between preferential orientation. film morphologies and CL characteristics are also investigated.

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Cathodoluminescence properties of $Ga_2O_3$ and ZnO nanomaterials ($Ga_2O_3$와 ZnO 나노물질의 CL특성)

  • Lee, Jong-Soo;Kang, Myung-Il;Park, Il-Woo;Sung, Man-Young;Kim, Sang-Sig
    • Proceedings of the KIEE Conference
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    • 2002.11a
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    • pp.97-98
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    • 2002
  • $Ga_2O_3$ nanobelts were synthesized from mechanically ground GaN powders with a thermal annealing in a nitrogen atmosphere. The nanobelts are with the range of about $10{\sim}200nm$ width and $10{\sim}50nm$ thickness. Three different ZnO nanomaterials (nanobelts, nanorods, and nanowires) were synthesized at three different substrate temperatures from the thermal evaporation of ball-milled ZnO powders at $1380^{\circ}C$. In cathodoluminescence(CL), the peak energy of near band-edge(NBE) emission was determined for nanobelts, nanorods, and nanowires.

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Effect of Hydrogen Radicals for Ion Implanted CVD Diamond Using Remote Hydrogen Plasma Treatment(RHPT)

  • Won, Jaihyung;Hatta, Akimitsu;Yagi, Hiromasa;Wang, Chunlei;Jiang, Nan;Jeon, Hyeongmin;Deguehi, Masahiro;Kitabatake, Makoto;Ito, Toshimichi;Sasaki, Takatomo;Hiraki, Akio
    • The Korean Journal of Ceramics
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    • v.4 no.1
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    • pp.15-19
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    • 1998
  • Defects formation of Chemical Vapor Deposition (CVD) diamond on $^4He^{2+}$ irradiation and after remote hydrogen plasma treatment(RHPT) were investigated by cathodoluminescence(CL). As calculated in the TRIM simulation, the light elements of $^4He^{2-}$ can be penetrated into the diamond bulk structure at 3~4 $\mu\textrm{m}$ depth. The effects of the implantation region were observed when 5 keV~20 keV electron energy (insight 0.3~4.0$\mu\textrm{m}$) of CL measurement was irradiated to diamond at temperature 80 K. After the RHPT, rehybridization of irradiation damaged diamond was studied. The intensity of 5RL center(intrinsic defect of C) was diminished. The 2.16 eV center (N-V center) occurring usually by annealing could not be seen after RHPT. The diamond was rehybridized by hydrogen radicals without etching and thermal degradation by the RHPT.

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Micro-Raman Spectroscopy and Cathodoluminescence Study of Cross-section of Diamond Film

  • Wang, Chun-Lei;Akimitsu Hatta;Jaihyung Won;Jaihyung Won;Nan Jinang;Toshimichi Ito;Takatomo Sasaki;Akio Hiraki;Zengsun Jin
    • The Korean Journal of Ceramics
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    • v.3 no.1
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    • pp.1-4
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    • 1997
  • Diamond film (24$\mu\textrm{m}$) were prepared by Microwave Plasma Chemical Vapor Deposition method from a reactive CO/H$_2$ mixtures. Micro-Raman spectroscopy and micro-cathodoluminescence study were carried out along the crosssection and correlated to SEM observation. CL image of cross-section was also investigated. Peak position, FWHM of Raman spectrum were determined using Lorentzing fit. The stress in this sample is 0.4~0.7 GPa compressive stress, and along the distance the compressive stress reduced. The Raman peak broadening is dominated by phonon life time reduction at grain boundaries and defect sites. Defects and impurities were mainly present inside the film, not at Silicon/Diamond interface.

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