• Title/Summary/Keyword: Codoping

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The Effects of Codoping of Be and Mg on Incorporation of Mn in GaAs

  • Yu, Fucheng;Gao, Cunxu;Parchinskiy, P.B.;Chandra, Sekar.P.V.;Kim, Do-Jin;Kim, Chang-Soo;Kim, Hyo-Jin;Ihm, Young-Eon
    • Korean Journal of Materials Research
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    • v.18 no.8
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    • pp.444-449
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    • 2008
  • Samples of GaMnAs, GaMnAs codoped with Be, and GaMnAs simultaneously codoped with Be and Mg were grown via low-temperature molecular beam epitaxy (LT-MBE). Be codoping is shown to take the Ga sites into the lattice efficiently and to increase the conductivity of GaMnAs. Additionally, it shifts the semiconducting behavior of GaMnAs to metallic while the Mn concentration in the GaMnAs solid solution is reduced. However, with simultaneous codoping of GaMnAs with Be and Mg, the Mn concentration increases dramatically several times over that in a GaMnAs sample alone. Mg and Be are shown to eject Mn from the Ga sites to form MnAs and MnGa precipitates.

EFFECTS OF ISOELECTRONIC IMPURITIES ON THE LIGHT EMISSION OF THE THIN-FILM ELECTROLUMINESCENCT DEVICES (박막 EL소자의 광방사에 있어서 등전자 불순물의 효과)

  • 박연수;곽민기;김현근;손상호;이상윤;이상걸
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1994.11a
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    • pp.79-80
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    • 1994
  • A systematic study on isoelectronic impurities in thin-film eletroluminescent devices (TFELD) has been made on the basis of the experimental analysis aimed at a survey for the blue-emitting materials. Codoping effects of isoelectronic impurities, such as oxygen(O), tellurium(Te), and lithium(Li), on the emissive characteristics of ZnS:Ce$^{3+}$ and ZnS:Tm$^{3+}$TFELD have been investigated by means of the X-ray diffraction studies, the Auger electron spectroscopy, the cathodoluminescent spectra, and the electroluminescent spectra. Experiment results reveal that oxygen codoping gives rise to an increase of the luminance, due to a suppression of the nonradiative energy transfer via sulfur vacancies Te codoping in ZnS:Ce$^{3+}$ TFELD result in a large change in the crystal field around Ce$^{3+}$ ions. Li codoping in ZnS:Tm$^{3+}$ TFELD causes the luminance to increase slightly, due to a lowering in the symmetry of Tm$^{3+}$ions. Likewise, the experimental results suggest strongly that an Auger-type enegy loss via lattece defects such an sulfur vacancies acts as a non-emissive in TFELD.ve in TFELD.

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Realization of p-type ZnO Thin Films Using Codoping N and Al by RF Magnetron Sputtering

  • Jin, Hu-Jie;So, Byung-Moon;Park, Bok-Kee;Park, Choon-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.107-108
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    • 2006
  • ZnO is a promising material for UV or blue LEDs p-Type ZnO thin films which are imperative for the p-n junction of LEDs are difficult to achieve because of strong compensation of intrinsic defects such as zinc interstitial and oxygen vacancy. The method of codoping group three elements and group five elements is effective for the realization of p-type ZnO films. In this study, We codoped N and Al m ZnO thin films by RF magnetron sputtering and annealed the films in sputtering chamber. Some films showed p-type conductivity m Seeback effect measurement.

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Room-temperature Magnetotransport in Degenerately Doped GaAs:(Mn,Be) by Virtue of the Embedded Ferromagnetic Clusters

  • Yu, Fu-Cheng;Kim, Do-Jin;Kim, Hyo-Jin;Ihm, Young-Eon
    • Journal of Magnetics
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    • v.10 no.3
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    • pp.103-107
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    • 2005
  • Magnetotransport is a prerequisite to realization of electronic operation of spintronic devices and it would be more useful if realized at room temperature. The effects of Be codoping on GaMnAs on magnetotransport were investigated. Mn flux was varied for growth of precipitated GaMnAs layers under a Be flux for degenerate doping via low-temperature molecular beam epitaxy. Magnetotransport as well as ferromagnetism at room temperature were realized in the precipitated GaAs:(Mn,Be) layers. Codoping of Be was shown to promote formation of MnGa clusters, and annealing process further stabilized the cluster phases. The room-temperature magnetic properties of the layers originate from the ferromagnetic clusters of MnGa and MnAs embedded in GaAs. The degenerately doped metallic GaAs matrix allowed the visualization of the magnetotransport through anomalous Hall effect.

Optical characterization on undoped and Mg-doped GaN implanted with Eu (Eu이 이온주입된 undoped와 Mg-doped GaN의 분광 특성 연구)

  • Lee, So-Won;Moon, Joo-Young;Rhee, Seuk-Joo
    • Journal of the Korean Vacuum Society
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    • v.17 no.4
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    • pp.346-352
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    • 2008
  • Eu sites and the effect of Mg codoping were investigated in Eu-implanted GaN films. Photoluminescence (PL) and PL excitation spectroscopies were performed on 620nm $^5D_0\;{\rightarrow}\;^7F_2$ Eu ionic level transition and revealed the existence of 4 different Eu sites including the known 2 sites. PL intensity from one of the sites increased by a factor of 1.6 by the Mg-codoping. The enhancement of PL by Mg-codoping was less pronounced than Er- and Nd-implanted GaN, in which the trap-mediated energy transfer dominates. In GaN:Eu the above-gap excitation transfers the energy directly to the Mg related Eu site.

Thermal stabilizing effect of Yb3+ Er3+ codoping into TiO2 powder prepared by sol-gel method and its upconversion characteristic (Yb3+ Er3+ ions 동시도핑에 의한 TiO2 분말의 열적 안정성 증가효과와 upconversion 특성 연구)

  • Eun, Jong-Won;Oh, Dong-Keun;Kim, Kwang-Jin;Hong, Tae-Ui;Jeong, Seong-Min;Choi, Bong-Geun;Shim, Kwang-Bo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.4
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    • pp.173-177
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    • 2010
  • Thermal stabilizing effect of $Yb^{3+},\;Er^{3+}$ codoping into $TiO_2$ powder prepared by sol-gel method and its upconversion characteristics were analyzed. The effect of $TiO_2:Yb^{3+},\;Er^{3+}$ ions on crystallinity and phase transition was studied by X-ray diffraction (XRD). The change of band-gap energy induced from Yb and Er codoping was analyzed by UV-Vis. The band-gap energy of $TiO_2$ have been slightly narrowed by $Yb^{3+},\;Er^{3+}$ codoping, which indicated that the $Yb^{3+},\;Er^{3+}$ ions can enhance the photo-catalytic property of $TiO_2$. green and red up-conversions of $Yb^{3+}$ and $Er^{3+}$ co-doped $Y_2O_3:Yb^{3+},\;Er^{3+}$ phosphor were analyzed by PL equipped with 980 nm laser.

Effects of Codoping with Fluorine on the Properties of ZnO Thin Films

  • Heo, Young-Woo;Norton, D.P.
    • Journal of the Korean Ceramic Society
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    • v.43 no.11 s.294
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    • pp.738-742
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    • 2006
  • We report on the effects of co-doping with fluorine on properties of ZnO thin films grown by pulsed-laser deposition. The transport characteristics of Ag-F and Li-F codoped ZnO films were determined by Hall-effect measurements at room temperature. Ag-F codoped ZnO films showed n-type semiconducting behaviors. An ambiguous carrier type was observed in Li-F codoped ZnO films grown at a temperature of 500$^{\circ}C$ with the oxygen pressures of 20 and 200 mTorr. The qualities of the codoped ZnO films were studied by X-ray diffraction, atomic force microscopy, X-ray photoemission spectroscopy, and photoluminescence.

The Phase Transition and Thermochromic Characteristics of W/Mg-codoped Monoclinic VO2 Nanoparticle and Its Composite Film

  • Park, Heesun;Kim, Jongmin;Jung, Young Hee;Kim, Yeong Il
    • Journal of the Korean Chemical Society
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    • v.61 no.2
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    • pp.57-64
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    • 2017
  • Monoclinic $VO_2(M)$ nanoparticles codoped with 1.5 at. % W and 2.9 at. % Mg were synthesized by the hydrothermal treatment and post-thermal transformation method of $V_2O_5-H_2C_2O_4-H_2O$ with $Na_2WO_4$ and $Mg(NO_3)_2$. The composite thin film of the W/Mg-codoped $VO_2(M)$ with a commercial acrylic block copolymer was also prepared on PET substrate by wet-coating method. The reversible phase transition characteristics of the codoped $VO_2(M)$ nanoparticles and the composite film were investigated from DSC, resistivity and Vis-NIR transmittance measurements compared with the undoped and Wdoped $VO_2(M)$ samples. Mg-codoping into W-doped $VO_2(M)$ nanoparticles synergistically enhanced the transition characteristics by increasing the sharpness of transition while the transition temperature ($T_c$) lowered by W-doping was maintained. The codoped composite film showed the prominently enhanced NIR switching efficiency compared to only W-doped $VO_2(M)$ film with a lowered $T_c$.