B₂O₃와 CuO가 첨가된 Ba(Mg_1/3Nb_2/3)O₃ 세라믹스의 저온소결과 마이크로파 유전특성 연구

임종봉,손진옥,남산,유명재,이우성,강남기,이확주,Lim, Jong-Bong,Son, Jin-Ok,Nahm, Sahn,Yoo, Myong-Jea,Lee, Woo-Sung,Kang, Nam-Kee,Lee, Hwack-Joo 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.1

B$_2$O$_3$ added Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (BBMN) ceramics were not sintered below 900 $^{\circ}C$. However, when CuO was added to the BBMN ceramic, it was sintered even at 850 $^{\circ}C$. The amount of the $Ba_2$B$_2$O$_{5}$ second phase decreased with the addition of CuO. Therefore, the CuO additive is considered to react with the B$_2$O$_3$ inhibiting the reaction between B$_2$O$_3$ and BaO. Moreover, it is suggested that the solid solution of CuO and B$_2$O$_3$ might be responsible for the decrease of the sintering temperature of the specimens. A dense microstructure without pores was developed with the addition of a small amount of CuO. However, a porous microstructure with large pores was formed when a large amount of CuO was added. The bulk density, the dielectric constant ($\varepsilon$$_{r}$) and the Q-value increased with the addition of CuO but they decreased when a large amount of CuO was added. The variations of those properties are closely related to the variation of the microstructure. The excellent microwave dielectric properties of Qxf = 21500 GHz, $\varepsilon$$_{r}$ = 31 and temperature coefficient of resonance frequency($\tau$$_{f}$) = 21.3 ppm/$^{\circ}C$ were obtained for the Ba(Mg$_{1}$3/Nb$_{2}$3/)O$_3$+2.0 mol%B$_2$O$_3$+10.0 mol%CuO ceramic sintered at 875 $^{\circ}C$ for 2 h.h.2 h.h.

High-Performance MoS₂/CuO Nanosheet-on-One-Dimensional Heterojunction Photodetectors

Um, Doo-Seung,Lee, Youngsu,Lim, Seongdong,Park, Seungyoung,Lee, Hochan,Ko, Hyunhyub American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.49

<P>van der Waals heterostructures based on stacked two-dimensional (2D) materials provide novel device structures enabling high-performance electronic and optoelectronic devices. While 2D-2D or 2D bulk heterostructures have been largely explored for fundamental understanding and novel device applications, 2D one-dimensional (1D) heterostructures have been rarely studied because of the difficulty in achieving high-quality heterojunctions between 2D and 1D structures. In this study, we introduce nanosheet-on-1D van der Wags heterostructure photodetectors based on a wet-transfer printing of a MoS2 nanosheet on top of a CuO nanowire (NW). MoS2/CuO nanosheet-on-1D photodetectors show an excellent photocurrent rectification ratio with an ideality factor of 1.37, which indicates the formation of an atomically sharp interface and a high-quality heterojunction in the MoS2/CuO heterostructure by wet-transfer-enhanced van der Waals bonding. Furthermore, nanosheet-on-1D heterojunction photodetectors exhibit excellent photodetection capabilities with an ultrahigh photoresponsivity (similar to 157.6 A/W), a high rectification ratio (similar to 6000 at +/- 2 V), a low dark current (similar to 38 fA at -2 V), and a fast photoresponse time (similar to 34.6 and 51.9 ms of rise and decay time), which cannot be achievable with 1D-on-nanosheet heterojunction photodetectors. The wet transfer printing of nanosheet-on-1D heterostructures introduced in this study provides a robust platform for the fundamental study of various combinations of 2D-on-1D heterostructures and their applications in novel heterojunction devices.</P>

Stable, High Voltage Li_0.85Ni_0.46Cu_0.1Mn_1.49O₄ Spinel Cathode in a Lithium-Ion Battery Using a Conversion-Type CuO Anode

Verrelli, Roberta,Scrosati, Bruno,Sun, Yang-Kook,Hassoun, Jusef American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.7

<P>We report in this work a copper-doped Li<SUB>0.85</SUB>Ni<SUB>0.46</SUB>Cu<SUB>0.1</SUB>Mn<SUB>1.49</SUB>O<SUB>4</SUB> spinel-structured compound prepared by an easy, two-steps coprecipitation and solid state process and used in a lithium-ion battery in combination with a CuO-based anode. We show that the spinel-type cathode adopts unique morphology, characterized by well-developed, crystalline and aggregated microparticles, that considerably reduces the occurrence of side reactions. This cathode material can operate in a lithium cell at voltages as high as 5.3 V without sign of electrolyte decomposition, delivering a capacity of about 100 mA h g<SUP>–1</SUP> with high retention and high Coulombic efficiency over prolonged cycling. The combination of the Li<SUB>0.85</SUB>Ni<SUB>0.46</SUB>Cu<SUB>0.1</SUB>Mn<SUB>1.49</SUB>O<SUB>4</SUB> cathode with a conversion-type, CuO–MCMB anode results in a new type of lithium ion battery characterized by a voltage value of 3.4 V, a stable capacity of 100 mA h g<SUP>–1</SUP> and a high Coulombic efficiency (exceeding 95%). Expected low cost, safety, and environmental compatibility are additional advantages of the lithium-ion cell reported here.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-7/am500499a/production/images/medium/am-2014-00499a_0008.gif'></P>

Facile preparation and optoelectronic properties of CuO nanowires for violet light sensing

Ko, Y.H.,Nagaraju, G.,Lee, S.H.,Yu, J.S. North-Holland 2014 Materials Letters Vol.117 No.-

CuO nanowires (NWs) were prepared on Cu foil substrates via a simple thermal oxidation, which exhibited good crystal and optical properties. By means of a conventional furnace at 500<SUP>o</SUP>C for 3h, the CuO NWs were grown vertically with high aspect ratio with the lengths/widths of ~5-15μm/~20-70nm. To investigate photoresponse characteristics, the multiple CuO NWs were deposited between metal electrodes using the CuO NWs dispersed in 1-butanol solution. Under the violet light multiple switching, the fabricated sample showed a good photocurrent switching behavior with a short reset time.

Resonance tunneling phenomena by periodic potential in type-II superconductor

Lee, Yeong Seon,Kang, Byeongwon The Korea Institute of Applied Superconductivity a 2014 한국초전도저온공학회논문지 Vol.16 No.1

We calculated the resonance tunneling energy band in the BCS gap for Type-II superconductor in which periodic potential is generated by external magnetic flux. In this model, penetrating magnetic flux was assumed to be in a fixed lattice state which is not moving by an external force. We observed the existence of two subbands when we used the same parameters as for the $Nd_{1.85}Ce_{0.15}CuO_X$ thin film experiment. The voltages at which the regions of negative differential resistivity (NDR) started after the resonant tunneling ended were in a good agreement with the experimental data in the field region of 1 T - 2.2 T, but not in the high field regions. Discrepancy occurred in the high field region is considered to be caused by that the potential barrier could not be maintained because the current induced by resonant tunneling exceeds the superconducting critical current. In order to have better agreement in the low field region, more concrete designing of the potential rather than a simple square well used in the calculation might be needed. Based on this result, we can predict an occurrence of the electromagnetic radiation of as much difference of energy caused by the 2nd order resonant tunneling in which electrons transit from the 2nd band to the 1st band in the potential wells.

Activation of formyl CH and hydroxyl OH bonds in HMF by the CuO(1 1 1) and Co₃O₄(1 1 0) surfaces: A DFT study

Ren, Jun,Song, Kai-he,Li, Zhenhuan,Wang, Qiang,Li, Jun,Wang, Yingxiong,Li, Debao,Kim, Chan Kyung Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.456 No.-

<P><B>Abstract</B></P> <P>The first principle calculations with on-site Coulomb repulsion U terms were carried out to investigate the 5-hydroxymethylfurfural (HMF) adsorption on the CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces, two widely used oxidation catalysts. The adsorption of HMF molecule is energetically favoured in both cases, and HMF is more inclined to bridge adsorption via hydroxyl and formyl groups binding with surface O and metal sites. Moreover, the adsorption energy relies on both the coordination type of surface lattice oxygen to which the H atom binds and the formation of H-bond involving hydroxyl and formyl groups on the adsorbed HMF. Also, the hydroxyl OH bond breaking is very easy and is likely to be the first step in HMF oxidation, and then the OH insertion reaction to produce 2,5-furandicarboxylic acid (FDCA). The corresponding experimental results also show that the CuO and Co<SUB>3</SUB>O<SUB>4</SUB> surfaces are promising candidate catalysts.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces catalyze the oxidation of 5-hydroxymethylfurfural (HMF). </LI> <LI> Initial binding was formed through bridged-adsorption with O atoms in HMF. </LI> <LI> Oxidation reaction proceeds through the OH bond breaking pathway. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic potential energy diagram for the formyl CH and hydroxyl OH bonds of HMF dissociation on CuO(1 1 1) and Co<SUB>3</SUB>O<SUB>4</SUB>(1 1 0) surfaces. Obviously, the hydroxyl OH bond breaking is easier than that of the formyl CH bond on the two surfaces, which indicates the first step of oxidation of HMF to FDCA should be hydroxyl OH bond breaking.</P> <P>[DISPLAY OMISSION]</P>

Fabrication of Hierarchical CuO Microspheres

Ha-Chul Song,Seong-Hun Park,Young-Duk Huh* 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.3