• 제목/요약/키워드: S vacancy

검색결과 123건 처리시간 0.081초

Positron Annihilation Study of Vacancy Type Defects in Ti, Si, and BaSrFBr:Eu

  • Lee, Chong Yong
    • Applied Science and Convergence Technology
    • /
    • 제25권5호
    • /
    • pp.85-87
    • /
    • 2016
  • Coincidence Doppler broadening and positron lifetime methods in positron annihilation spectroscopy has been used to analyze defect structures in metal, semiconductor and polycrystal, respectively. The S parameter and the lifetime (${\tau}$) value show that the defects were strongly related with vacancies. A positive relationship existed between the scanning electron microscope (SEM) images and the positron annihilation spectroscopy (PAS). According to the SEM images and PAS results, measurements of the defects with PAS indicate that it was more affected by the defect than the purity.

진공증착법으로 제작한 CdS 박막의 열처리효과 (Heat-treatment Effects of CdS Thin Films Fabricated by Thermal Evaporation Method)

  • 박태성;진교원;김영호;한은주;김근묵
    • 한국재료학회지
    • /
    • 제7권11호
    • /
    • pp.981-985
    • /
    • 1997
  • 열증착법에 의해서 온도 85$^{\circ}C$인 glass기판 위에 CdS 박막을 제작하였다. 두께가 200nm정도로 측정된 CdS박막은 공기 중에서 온도 25$0^{\circ}C$-55$0^{\circ}C$범위에서 각각 30분간 열처리 되었으며 이들 시료에 대하여 4-point probe, XRD, SEM, UV-Spectrophotometer 및 광발광 측정으로 전기적 광학적 특성을 조사하였다. 이들의 일련의 실험값은 열처리 온도 37$0^{\circ}C$ 근처에서 구조의 변화를 보여주었는데, 열처리 온도에 대한 비저항아니 XRD, SEM 의 측정은 cubic로부터 hexagonal구조로의 변환을 나타내었다. 특히 상온에서 측정한 광발광에서 green edge emission(GEE)피이크가 2.42eV를 나타내었는데 이 때의 발광 중심은 열처리할 때 생긴 S-vacancy에 보상된 산소로 이루어진 'CdO'의 악셉터준위에 기인하는 것으로 해석되며 그 이온화 에너지는 약 0.16eV이었다.

  • PDF

ZnS:Cu 형광체의 전계 발광 및 가속열화 특성 (Electroluminescent and Accelerated Aging Properties of ZnS:Cu Phosphor)

  • 이종찬;황명근;박대희
    • 한국조명전기설비학회:학술대회논문집
    • /
    • 한국조명전기설비학회 2001년도 학술대회논문집
    • /
    • pp.13-16
    • /
    • 2001
  • In this paper, the emission and aging properties of ZnS:Cu electroluminescent device were experiment respectively at room temperature and 7$0^{\circ}C$ relative humidity 100%. ZnS:Cu and BaTiO$_3$were respectively used for phosphor and dielectric. While AC 100V on 400Hz frequency were applied to the devices at room temperature and 70$_3$relative humidity 100%, the change of brightness were measured and compared. The surface of aged devices were investigated by scanning electron microscope. With the continuously operated environment of room temperature and 7$0^{\circ}C$ relative humidity 100%, the decay time were measured and the dark spot and aging status on the surface of the device were investigated. ZnS:Cu electroluminescent properties were deteriorated by the Increased temperature and humidity. Also the deteriorated properties were confirmed by the brightness and surface chanties of device, and the aging mechanism from the simulation on sulfur vacancy and deep tracts density.

  • PDF

Enhanced superconducting properties of MgB2 by doping the carbon quantum dots

  • K.C., Chung;S.H., Jang;Y.S., Oh;S.H., Kang
    • 한국초전도ㆍ저온공학회논문지
    • /
    • 제24권4호
    • /
    • pp.55-58
    • /
    • 2022
  • Carbon-based doping to MgB2 superconductor is the simplest approach to enhance the critical current densities under magnetic fields. Carbon quantum dots is synthesized in this work as a carbon provider to MgB2 superconductors. Polyvinyl Pyrrolidone is pyrolyzed and dispersed in dimethylfomamide solvent as a dopant to the mixture of Mg and B powders. Doped MgB2 bulk samples clearly show the decrease of a-axis lattice constant, grain refinements, and broadening of FWHM of diffraction peaks compared to un-doped MgB2 possibly due to the carbon substitution and/or boron vacancy at the boron site in MgB2 lattice. Also, high-field Jc for the doped MgB2 is enhanced significantly with the crossover about 3 T at 5 & 20 K when increasing the doping of carbon quantum dots.

Effects of Mg Suppressor Layer on the InZnSnO Thin-Film Transistors

  • Song, Chang-Woo;Kim, Kyung-Hyun;Yang, Ji-Woong;Kim, Dae-Hwan;Choi, Yong-Jin;Hong, Chan-Hwa;Shin, Jae-Heon;Kwon, Hyuck-In;Song, Sang-Hun;Cheong, Woo-Seok
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • 제16권2호
    • /
    • pp.198-203
    • /
    • 2016
  • We investigate the effects of magnesium (Mg) suppressor layer on the electrical performances and stabilities of amorphous indium-zinc-tin-oxide (a-ITZO) thin-film transistors (TFTs). Compared to the ITZO TFT without a Mg suppressor layer, the ITZO:Mg TFT exhibits slightly smaller field-effect mobility and much reduced subthreshold slope. The ITZO:Mg TFT shows improved electrical stabilities compared to the ITZO TFT under both positive-bias and negative-bias-illumination stresses. From the X-ray photoelectron spectroscopy O1s spectra with fitted curves for ITZO and ITZO:Mg films, we observe that Mg doping contributes to an enhancement of the oxygen bond without oxygen vacancy and a reduction of the oxygen bonds with oxygen vacancies. This result shows that the Mg can be an effective suppressor in a-ITZO TFTs.

HPHT(고온고압)에 의해 처리된 type IIa 천연 다이아몬드의 감별에 관한 연구 (A study on the identification of type IIa natural diamonds treated by the HPHT method)

  • 김영출;최현민
    • 한국결정성장학회지
    • /
    • 제14권1호
    • /
    • pp.21-26
    • /
    • 2004
  • HPHT(고온고압) 처리된 type IIa 다이아몬드의 분광분석 결과를 나타내었다. 그리고 HPHT 처리된 다이아몬드 spectrum의 특성을 이와 유사한 color와 type을 가진 처리되지 않은 다이아몬드와 비교하였다. 325nm 에서 여기된 He/Cd laser로는 HPHT 처리된 다이아몬드와 처리되지 않은 다이아몬드에 현저한 변화가 있음을 알 수 있었는데 이는 HPHT 처리된 다이아몬드의 spectrum에서 H3, H4에 관련된 peak가 제거되고 N3 system에 관련된 peak의 emission이 증가함을 보여 주었다. 또한 514nm에서 여기된 Ar-ion laser로 측정된 spectrum은 575nm와 637.1 nm에서 Nitrogen과 vacancy가 관련되어있는 N-V center가 발견 되었는데 이러한 center가 존재하고 있을 경우 637.1 nm의 FWHM의 값은 HPHT 처리된 다이아몬드와 처리되지 않은 다이아몬드를 구분할 수 있음을 보여주었다. 본 실험에서 측정된 HPHT 처리된 다이아몬드의 637.1nm $(N-V)^-$의 FWHM 값은 $19.8{\textrm}{cm}^{-1}$에서$32.1{\textrm}{cm}^{-1}$였다.

A-site Vacancy가 0.97Bi0.5+x(Na0.78K0.22)0.5-3xTiO3-0.03LaFeO3 무연압전 세라믹스의 압전특성에 미치는 영향 (Effects of A-site Vacancies on the Piezoelectric Properties of 0.97Bi0.5+x(Na0.78K0.22)0.5-3xTiO3-0.03LaFeO3 Lead-free Piezoelectric Ceramics)

  • 박정수;이규탁;조정호;정영훈;백종후;윤지선
    • 한국세라믹학회지
    • /
    • 제51권6호
    • /
    • pp.527-532
    • /
    • 2014
  • $0.97Bi_{0.5+x}(Na_{0.78}K_{0.22})_{0.5-3x}TiO_3-0.03LaFeO_3$ lead-free piezoelectric ceramics were fabricated by a solid state reaction method. $LaFeO_3$ additives were added to $Bi_{0.5}(Na_{0.78}K_{0.22})_{0.5}TiO_3$ for volatile compensation of bismuth and sodium ions in the sintering process. To create A-site vacancies, the mole ratio and charge valence of A-site ions ($Bi^{3+}$, $Na^+$ and $K^+$) were controlled. The improved piezoelectric properties were observed by addition of $LaFeO_3$ and control of A-site vacancies. In particular, a $d_{33}^*(S_{max}/E_{max})$ value of 614pm/V and an electric field induced strain of 0.33% was observed in $0.97Bi_{0.505}(Na_{0.78}K_{0.22})_{0.485}TiO_3-0.03LaFeO_3$ ceramic.

산소공공 농도에 따른 MZO 투명전도성 박막의 구조적 및 전기적 특성 (Effect of the Concentration of Oxygen Vacancies on the Structural and Electrical Characteristics of MZO Thin Films)

  • 이종현;이규만
    • 반도체디스플레이기술학회지
    • /
    • 제22권1호
    • /
    • pp.18-22
    • /
    • 2023
  • We have investigated the effect of the concentration of oxygen vacancies on the characteristics of Mo-doped ZnO (MZO) thin films for the TCO (transparent conducting oxide). For this purpose, MZO thin films were deposited by RF magnetron sputtering at different substrate temperature from room temperature to 300℃. The electrical resistivity of the MZO films decreases with increasing substrate temperature up to 100℃ and then gradually increases at higher temperatures. To investigate the influences of the ambient gases, the flow rate of oxygen and hydrogen in argon was varied from 0.1 sccm to 0.5 sccm. The MZO thin films were preferentially oriented to the (002) direction, regardless of the ambient gases used. The electrical resistivity of the MZO thin films increased with increasing O2 flow rates, whereas the electrical resistivity decreased sharply under an Ar+H2 atmosphere and was nearly the same, regardless of the H2 flow rate used. As the oxygen vacancy concentration increases, the resistivity intended to decrease. In conclusion, Oxygen vacancy affects the MZO thin film's electrical characteristics. All the films showed an average transmittance of over 80% in the visible range.

  • PDF