• Bulletin of the Korean Chemical Society
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• 제15권9호
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• pp.713-718
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• 1994

Manganese-incorporated neodymium oxide systems with a variety of Mn mol% were prepared to investigate the effect of doping on the electrical properties of neodymium oxide. XRD, XPS, SEM, DSC, and TG techniques were used to analyze the specimens. The systems containing 2, 5, 8, and 10 mol% Mn were found to be solid solutions by X-ray diffraction analysis and the lattice parameters were obtained for the single-phase hexagonal structure by the Nelson-Riley method. The lattice parameters, a and c, decreased with increasing Mn mol%. Scanning electron photomicrographs of the specimens showed that the grain size decreased with increasing Mn mol%. The curves of log conductivity plotted as a function of 1/T in the temperature range from 500 to 1000$^{\circ}C$ at $PO_2$'s of $10^{-5}$ to $10^{-1}$ atm for the specimens were divided into high-and low-temperature regions with inflection points near 820-890$^{\circ}C$. The activation energies obtained from the slopes were 0.53-0.87 eV for low-temperature region and 1.40-1.91 eV for high-temperature region. The electrical conductivities increased with increasing Mn mol% and $PO_2$, indicating that all the specimens were p-type semiconductors. At $PO_2$'s below $10^{-3}$ atm, the electrical conductivity was affected by the chemisorption of oxygen molecule in the temperature range of 660 to 850$^{\circ}C$. It is suggested that electron holes generated by oxygen incorporation into the oxide are charge carriers for the electrical conduction in the high-temperature region and the system includes ionic conduction owing to the diffusion of oxygen atoms in the low-temperature region.

• Journal of Electrochemical Science and Technology
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• 제5권2호
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• pp.49-52
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• 2014

Graphene nanosheets (GNS), nitrogen-doped graphene nanosheets (N-GNS), and sulfur-doped graphene nanosheets (S-GNS) were successfully synthesized, and their catalytic effects on the oxygen reduction reaction (ORR) in $Li-O_2$ batteries were compared. The S-GNS electrode exhibited the highest ORR catalytic activity, resulting in enhanced discharge capacity and power capability. We attributed the enhanced ORR catalytic activity to the increased defect sites on graphene.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.315-315
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• 2011

The ring formation and electronic properties of furan adsorbed on graphene layers grown on 6H-SiC(0001) has been investigated using atomic force microscopy (AFM), near edge X-ray absorption fine structure (NEXAFS) spectra for the C K-edge, and high resolution photoemission spectroscopy (HRPES). Moreover, we observed that furan molecules adsorbed on graphene could be used for chemical functionalization via the lone pair of electrons on the oxygen group, allowing chemical doping. We also found that furan spontaneously formed rings with one of three different bonding configurations and the electronic properties of the ring formed by furan on graphene can be described using by AFM, NEXAFS and HRPES, respectively.

• 한국광학회:학술대회논문집
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• 한국광학회 2001년도 제12회 정기총회 및 01년도 동계학술발표회
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• pp.14-15
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• 2001

본 강좌에서는 광통신과 센서 분야에서 최근 실용화되고 있는 중요한 소자인 광섬유 격자(fiber grating)에 대해, 그 원리와 종류, 제작 방법, 시뮬레이션 기법, 광통신용 응용 및 광섬유 격자 센서 시스템의 구현 기법 등에 대해 설명한다. 별도로 제공되는 강의록에서 이에 대해 보다 구체적으로 기술할 것인 바, 그 요약은 아래와 같다. 광섬유에 굴절률 변화 패턴을 만들 수 있다는 사실은 1978년 Hill 등에 의해 발견되었고, 1989년 Meltz 등에 의해, 자외선(UV) 레이저를 광섬유 측면에 조사하여 광섬유 코어(core)의 특정 부위에 광섬유 격자를 만드는 방법이 고안되었다. 광섬유에 격자가 새겨지는 원인에 대한 이론은 여러 가지가 있고 이들이 복합적으로 작용하지만, 중요한 요인은 산소가 빠진 게르마늄과 관련된(oxygen deficient germania related) 결함이다. 따라서, 게르마늄(Ge)이 높게 도우핑(doping)된 광섬유에 격자가 잘 새겨진다. 보통의 단일 모드 광섬유도 수소처리(hydrogenation)를 하면 자외선에 대한 광민감성(photosensitivity)을 증가시킬 수 있어 격자의 제작이 가능하다. (중략)

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.540-542
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• 2009

Phosphorus doped ZnO (PZO) thin films were deposited on $SiO_2$/n-Si substrates using DC magnetron sputtering system varying oxygen partial pressures from 0 to 40 % under Ar atmosphere. The deposited films showed reduced n-type conductivity due to the compensating donor effects by phosphorus dopant. The bias-time stability shows relatively good stability over bias and time comparing to un-doped ZnO-based TFTs.

• 대한전자공학회논문지
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• 제17권5호
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• pp.43-47
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• 1980

전자선가열 도착법에 의해 ∼ 10-4 Torr의 산소 분권기중에서 In2O3 투명전도막을 제작하였으며, 막의 최적 훈착조건과 그의 전기적, 광학적 성질을 측정, 분석하였다. 최적 증착조건은 증착구도 3∼7 A/sec, 기판온도 300℃이상, SnO2 첨가률 2∼5 wt. % 이었으며, 이러한 조건하에서 막피 비저항은 2 × 10-4 Ω·cm 이었고, 가시광 투과률은 85∼90% 이었다.

• Applied Science and Convergence Technology
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• 제23권3호
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• pp.113-127
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• 2014

For more than five decades, silicon has dominated the semiconductor industry that supports memory devices, ICs, photovoltaic devices, etc. Photoluminescence (PL) is an attractive silicon characterization technique because it is contactless and provides information on bulk impurities, defects, surface states, optical properties, and doping concentration. It can provide high resolution spectra, generally with the sample at low temperature and room-temperature spectra. The photoluminescence properties of silicon at low temperature are reviewed and discussed in this study. In this paper, silicon bulk PL spectra are shown in multiple peak positions at low temperature. They correspond with various impurities such as In, Al, and Be, phonon interactions, for example, acoustical phonons and optical phonons, different exciton binding energies for boron and phosphorus, dislocation related PL emission peak lines, and oxygen related thermal donor PL emissions.

• 한국세라믹학회지
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• 제43권11호
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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.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.178-178
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• 2010

We have deposited aluminum-doped ZnO thin films on borosilicate glass by atomic layer deposition. Diethylzinc (DEZ) and dimethylaluminum isopropoxide (DMAIP) were used as the metal precursor and the Al-dopant, respectively. Water was used as an oxygen source. DMAIP was successfully used as an aluminum precursor for chemical vapor deposition and ALD. All deposited films showed n-type conduction. The resistivity decreased to a minimum and then increased with increasing the aluminum content. The carrier concentration increased and the carrier mobility decreased with increasing the DMAIP to DEZ pulse ratio. The average optical transmittance was nearly 80 % in the visible part of the spectrum. The absorption edge moved to the shorter wavelength region with increasing the DMAIP to DEZ pulse ratio. Our results indicate that DMAIP is suitable for Al doping of ZnO films.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 추계학술발표회초록집
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• pp.58-58
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• 2003

Silver doped ZnO (SZO) films were prepared by rf magnetron sputtering on glass substrates with extraordinary designed ZnO target. With the doping source for target, use AgNO$_3$ powder on a various rate (0, 2, and 4 wt.%). We investigated dependence of coating parameter such as dopant content in target and substrate temperature in the SZO films. The SZO films have a preferred orientation in the (002) direction. As amounts of the Ag dopant in the target were increased, the crystallinity and the transmittance and optical band gap were decreased. And the substrate temperature were increased, the crystallinity and the transmittance were increased. But the crystallinity and the transmittance of SZO films were retrograde at 200$^{\circ}C$. Upside facts were related with composition. In addition, the Oxygen K-edge features of the SZO films were investigated by using near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Changes of optical band gap of the SZO films were explained compared with XRD, XPS and NEXAFS spectra.