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  • Title/Summary/Keyword: Ga doped

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RF Magentron Sputtering deposited by ZnO:Ga thin film characterization for a transparent thin film transistor an application (투명 박막 트랜지스터 응용을 위한 RF Magnetron Sputtering으로 증착된 ZnO:Ga 박막의 특성)

  • Lee, Seok-Jin;Kwon, Soon-Il;Park, Seung-Beum;Jung, Tae-Hwan;Lim, Dong-Gun;Park, Jea-Hwan;Yang, Kea-Joon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.146-147
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    • 2008
  • In this paper we report upon an investigation into the effect of sputter RF power on the electrical properties of Gallium doped zinc oxide (ZnO:Ga) film. Structural, electrical and optical properties of the ZnO:Ga films were investigation in terms of the sputtering power. Working pressure fixed in 5 mtorr and RF powers the variable did with 50~100 W. The result, We were able to without substrate temperature obtain resistivity of 9.3×104Ωcm and optical transmittance of 90%.

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Electrical and Optical Characteristics of Isoelectronic Al-doped GaN Films

  • Lee, Jae-Hoon;Ko, Hyun-Min;Park, Jae-Hee;Hahm, Sung-Ho;Lee, Jung-Hee
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2002.11a
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    • pp.81-84
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    • 2002
  • The effects of the isoelectronic AI-doping of GaN grown by metal organic chemical vapor deposition were investigated for the first time using scanning electron microscopy (SEM), Hall measurements, photoluminescence (PL), and time-resolved PL. When a certain amount of Al was incorporated into the GaN films, the room temperature photoluminescence intensity of the films was approximately two orders larger than that of the undoped GaN. More importantly, the electron mobility significantly increased from 130 for the undoped sample to 500cm2/Vs for the sample grown at a TMAl flow rate of 10μmol/min, while the unintentional background concentration only increased slightly relative to the TMAl flow. The incorporation of Al as an isoelectronic dopant into GaN was easy during MOCVD growth and significantly improved the optical and electrical properties of the film. This was believed to result from a reduction in the dislocation-related non-radiative recombination centers or certain other defects due to the isoelectronic Al-doping.

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Phase Formation and Electrical Conductivity of Ba-Doped LaBaGaO4 Layered Perovskite (Ba 첨가 LaBaGaO4 층상 Perovskite의 생성상과 전기전도도)

  • Lee, Kyu-Hyoung;Kim, Jong-Hwa;Kim, Hye-Lim;Kim, Shin;Lee, Hong-Lim
    • Journal of the Korean Ceramic Society
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    • v.41 no.8
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    • pp.623-627
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    • 2004
  • Phase formation and electrical conduction behavior of Ba-doped LaBaGa O4 layered perovskite were studied. Orthorhombic single phase of K2Ni F4-type structure was observed for the composition range of 0x0.2 in the La_1+x/Ba_1+x/Ga O4_4-δ/ system by X-ray analysis. In the dry atmosphere, La_0.8/Ba_1.2/Ga_3.9/ exhibited mixed conduction of oxygen ion and hole (p-type) at high p( O2). However, in water vapor containing atmosphere, it showed proton conduction due to the incorporation of water into oxygen vacancies. As the temperature decreased, the contribution of proton conductivity to the total conduction increased and proton conduction was dominant below 350C. The activation energy for proton conduction was calculated as 0.72 eV.

Enhanced Hole Concentration of p-GaN by Sb Surfactant (Sb 계면활성제에 의한 p-GaN 박막의 홀농도 향상)

  • Kim, J.Y.;Park, S.J.;Moon, Y.B.;Kwon, M.K.
    • Journal of the Korean Vacuum Society
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    • v.20 no.4
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    • pp.271-275
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    • 2011
  • The role and effect of Sb surfactant on structure and properties of p type gallium nitride (GaN) epilayers have been investigated. It was found that there was a increase of hole concentration with Sb surfactant, compared to typical Mg-doped p-GaN. The structural and optical quality of p-GaN epilayers were accessed by x-ray diffraction, photoluminescence and atomic force microscope measurements. The results clearly show that the increase in hole concentration with Sb surfactant can be resulted from decrease in the dislocations and nitrogen point defects.

Magnetotransport of Be-doped GaMnAs (GaMnAs의 Be 병행 도핑에 의한 자기 수송 특성 연구)

  • Im W. S.;Yoon T. S.;Yu F. C.;Gao C. X.;Kim D. J.;Ibm Y. E.;Kim H. J.;Kim C. S.;Kim C. O.
    • Korean Journal of Materials Research
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    • v.15 no.1
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    • pp.73-77
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    • 2005
  • Motivated by the enhanced magnetic properties of Mg-codoped GaMnN ferromagnetic semiconductors, Be-codoped GaMnAs films were grown via molecular beam epitaxy with varying Mn flux at a fixed Be flux. The structural, electrical, and magnetic properties were investigated. GaAs:(Mn,Be) films showed metallic behavior while GaAs:Mn films showed semiconducting behavior as determined by the temperature dependent resistivity measurements. The Hall-effect measurements with varying magnetic field showed clear anomalous Hall effect up to room temperature proving ferromagnetism and magnetotransport in the GaAs:(Mn,Be) films. Planar Hall resistance measurement also confirmed the properties. The dramatic enhancement of the Curie temperature in GaMnAs system was attributed to Be codoping in the GaMnAs films as well as MnAs precipitation.

The Electrical and Optical Properties of Al-Doped ZnO Films Sputtered in an Ar:H2 Gas Radio Frequency Magnetron Sputtering System

  • Hwang, Seung-Taek;Park, Choon-Bae
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.2
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    • pp.81-84
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    • 2010
  • Al-doped ZnO (AZO) films were prepared by an Ar:H2 gas radio frequency (RF) magnetron sputtering system with a AZO (2wt) ceramic target at the low temperature of 100C and annealed in hydrogen ambient at the temperature of 300C. To investigate the influence of the H2 flow ratio on the properties of the AZO films, the H2 flow ratio was changed from 0.5% to 2%. As a result, the AZO films, deposited with a 1% H2 addition, showed a resistivity of 11.7×104Ωcm. When the AZO films were annealed at 300C for 1 hour in a hydrogen atmosphere, the resistivity decreased from 11.7×104Ωcm to 5.63×104Ωcm. The lowest resistivity of 5.63×104Ωcm was obtained by adding 1% hydrogen gas to the deposition and annealing process. The X-ray diffraction patterns of all the films showed a preferable growth orientation in the (002) plane. The spectrophotometer measurements showed that the transmittance of 85% was obtained by the film deposited with the H2 flow ratio of 1% at 940 nm for GaAs/GaAlAs LEDs.

Effects of Doping with Al, Ga, and In on Structural and Optical Properties of ZnO Nanorods Grown by Hydrothermal Method

  • Kim, Soaram;Nam, Giwoong;Park, Hyunggil;Yoon, Hyunsik;Lee, Sang-Heon;Kim, Jong Su;Kim, Jin Soo;Kim, Do Yeob;Kim, Sung-O;Leem, Jae-Young
    • Bulletin of the Korean Chemical Society
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    • v.34 no.4
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    • pp.1205-1211
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    • 2013
  • The structural and optical properties of the ZnO, Al-doped ZnO, Ga-doped ZnO, and In-doped ZnO nanorods were investigated using field-emission scanning electron microscopy, X-ray diffraction, photoluminescence (PL) and ultraviolet-visible spectroscopy. All the nanorods grew with good alignment on the ZnO seed layers and the ZnO nanorod dimensions could be controlled by the addition of the various dopants. For instance, the diameter of the nanorods decreased with increasing atomic number of the dopants. The ratio between the near-band-edge emission (NBE) and the deep-level emission (DLE) intensities (INBE/IDLE) obtained by PL gradually decreased because the DLE intensity from the nanorods gradually increased with increase in the atomic number of the dopants. We found that the dopants affected the structural and optical properties of the ZnO nanorods including their dimensions, lattice constants, residual stresses, bond lengths, PL properties, transmittance values, optical band gaps, and Urbach energies.

Electrical, Structural and Optical Characteristic Analysis of Al-doped ZnO Film Deposited by Atomic Layer Deposition (Atomic Layer Deposition으로 증착된 Al-doped ZnO Film의 전기적, 구조적 및 광학적 특성 분석)

  • Lim, Jung-Soo;Jeong, Kwang-Seok;Shin, Hong-Sik;Yun, Ho-Jin;Yang, Seung-Dong;Kim, Yu-Mi;Lee, Hi-Deok;Lee, Ga-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.6
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    • pp.491-496
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    • 2011
  • Al-doped ZnO film on glass substrate is deposited by ALD in low temperature, using 4-step process (DEZ-H2O-TMA-H2O). To find out the optimal film condition for TCO material, we fabricate Al-doped ZnO films by increasing Al doping concentration at 100C, so that the Al-doped film of 5 at% shows the lowest resistivity (1.057×102Ωcm) and the largest grain size (38.047 nm). Afterwards, the electrical and physical characteristics in Al-doped films of 5 at% are also compared in accordance with increasing deposition temperature. All the films show the optical transmittance over 80% and the film deposited at 250C demonstrates the superior resistivity (1.237×104Ωcm).

Synthesis and Luminescent Characteristics of BaGa2S4:Eu2+ Green Phosphor for Light Emitting Diode (LED용 BaGa2S4:Eu2+ 녹색 형광체의 합성 및 발광특성)

  • Kim, Jae-Myung;Park, Joung-Kyu;Kim, Kyung-Nam;Lee, Seung-Jae;Kim, Chang-Hae
    • Korean Journal of Materials Research
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    • v.16 no.12
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    • pp.761-765
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    • 2006
  • [ IIIII2(S,Se)4 ] structured of phosphor has been used at various field because those have high luminescent efficiency and broad emission band. Among these phosphors, the europium doped BaGa2S4 was prepared by solid-state method and had high potential application due to an emissive property of UV region. Also, the common sulfide phosphors were synthesized by using injurious H2SorCS2 gas. However, in this study BaGa2S4:Eu2+ phosphor in addition to excess sulfur was prepared under at 5% H2/95 reduction atmosphere. Thus, this process could be considered as large scale synthesis because of non-harmfulness and simplification. The photoluminescence efficiency of the prepared BaGa2S4:Eu2+ phosphor increased 20% than that of commercial SrGa2S4:Eu2+ phosphor. The prepared BaGa2S4:Eu2+ could be applied to green phosphor for white LED of three wavelengths.

Introduction of a Buffering Layer for the Interfacial Stability of LSGM-Based SOFCs (LSGM계 고체산화물 연료전지의 계면안정성을 위한 완층층의 도입)

  • Kim, Kwang-Nyeon;Moon, Jooho;Son, Ji-Won;Kim, Joosun;Lee, Hae-Weon;Lee, Jong-Ho;Kim, Byung-Kook
    • Journal of the Korean Ceramic Society
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    • v.42 no.9 s.280
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    • pp.637-644
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    • 2005
  • In order to find a proper buffering material which can prohibit an unwanted interfacial reaction between anode and electrolyte of LSGM-based SOFC, we examined a gadolinium doped ceria and scandium doped zirconia as a candidate. For this examination, we investigated the microstructural and phase stability of the interface under different buffering layer conditions. According to the investigation, ceria based material induced a serious La diffusion out of the LSGM electrolyte resulted in the formation of very resistive LaSrGa3O7 phase at the interface. On the other hand zirconia based material was directly reacted with LSGM electrolyte and thus produced very resistive reaction products such as La2Zr2O7,Sr2ZrO4,LaSrGaO4andLaSrGa3O7. From this study we found that an improper buffering material induced the higher internal cell resistance rather than an interfacial stability.