• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.50-59
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• 1992

By means of X-ray photoelectron spectroscopy(XPS), the initial stages of the oxidation of the cleaved CdTe (110) surface and the sputtered CdTe surface with oxygen exposure are invetigated. From the analyses of the spectra of Te 3dsn, Cd 3d5/2, 0 ls and Cd MNN Auger lines, it is shown that two oxygen atoms bond to one Te atom at the initial stages.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.111-111
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• 2003

반도체 나노결정은 양자구속효과(quantum confinement effect)에 의한 광학적인 특성을 갖기 때문에 광전자공학(optoelectronic), 광전지(photovoltaic)분야에 응용하려는 연구가 활발히 진행되고 있다. 본 연구에서는 고순도의 CdTe 나노결정을 1-thioglycerol 표면 완화제(surface stabilizer)로 사용하여 수용액 상태로 합성하였다. 모든 실험은 $N_2$ 분위기의 삼각플라스크에서 실험하였다. Cadmium 소오스로는 Cd(CIO$_4$)$_2$.6$H_2O$(Cadmium perchlorate hydrate-Aldrich)를 사용하였고 Tellurium 소오스로는 A1$_2$Te$_3$(Aluminum telluride-CERAC)와 H$_2$SO$_4$가 반응하여 H$_2$Te gas가 주입되도록 하였다. 합성된 CdTe 나노결정은 core-shell 형태로 존재하며 결정크기에 따른 특성분석을 위해서 High Resolution Transmission Electron Microscope (HRTEM), Photoluminescence spectroscopy, X-ray diffraction(XRD), UV-vis absorption spectra 분석을 하였다 또한 CdTe 나노결정을 나노와이어로 제작하여 CdTe 나노결정을 이용한 태양전지 제작에 응용하고자 한다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.308-308
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• 2012

Electrodeposition of thermoelectric materials, including binary and ternary compounds, have been attracting attentions, because its many advantages including cost-effectiveness, rapid deposition rate, and ease of control their microstructure and crystallinity by adjusting electrodeposition parameters. In this work, $Bi_xTe_y$ films were potentiostatically electrodeposited using Au/Ni(80/20 nm)/Si substrate as the working electrode in solutions consisting of 10mM $TeO_2$ and 1M $HNO_3$ where $Bi(NO_3)_3$ was varied from 2.5 to 10 mM. Prior to electrodeposition potentiostatically, linear sweep voltammograms (LSV) were acquired with a standard three-electrode cell. The $Bi_xTe_y$ films deposited using the electrolyte containing low Bi ions shows p-type conductivity, which might be attributed by the large incorporation of Te phases. Near stoichiometric $Bi_2Te_3$ thin films were obtained from electrolytes containing 5mM $Bi(NO_3)_3$. This film shows the maximum Seebeck coefficient of $-100.3{\pm}12.7{\mu}V/K$. As the increase of Bi ions in electrolytes decreases the Seebeck coefficient and resistivity. The maximum power factor of $336.2{\mu}W/m{\cdot}K^2$ was obtained from the film deposited using the solution of 7.5mM $Bi(NO_3)_3$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.89-93
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• 1999

The properties and effects of the electrodeposited CdTe compound film on the porous silicon. To find ways to achieve good mechanical contact on the nanostructure porous silicon layer while keeping the interface transparent, we tried to electrodeposit a CdTe compound film on the porous silicon surface. The CdTe compound film was fabricated with -2.3V vs. Ag/AgCl potential difference in the electrolyte solution containing 1M of $CdSO_4$and 1 mM of $TeO_4$. X-ray diffraction results confirmed the existence of CdTe compound film on the porous silicon surface. Auger depth profile showed that Cd and Te were uniformly distributed up to a 80 nm distance from the surface. The photoluminescence of the sample with a CdTe compound film was weaker in intensity than that without the film and the maximum wavelength was shifted to the higher energy. These results indicate that the contacting CdTe compound film was infiltrated to the nanostructure of porous silicon.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.167.1-167.1
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• 2007

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.83-90
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• 1990

The semiconducting $(Pb_1\;_xSn_x)_1$ $_yTe_y$, one of the low - temperature thermoelectric materials, has been prepared and its chemical composition and nonstoichiometry has been analyzed. The content of Pb in the specimens was determined by the complexometric back - titration method with EDTA and Pb(II) standard solutions. Te - content was analyzed with the redox titration method. The electrical conductivity and the thermoelectric power have also been measured by the DC 4 - probe and the heat-pulse technique, respectively. All of the specimens showed a nonstoichiometric behavior in their chemical compositions (Te excess), thus gave rise to a p - type semiconducting property, and the nonstoichoimetry became bigger as the Sn - content increased. The thermoelectric power vs. temperature results have been analyzed upon the basis of the Fermi level vs. temperature profiles in the saturation regime. The specimen of x=0.1 evolved a transition from p - to n - type property at about 670K, which has been explained by the fact that the mobility of electrons is bigger than that of holes in the temperature range of the intrinsic regime.

• Applied Science and Convergence Technology
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• v.23 no.6
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• pp.392-397
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• 2014

CuO nanotubes are synthesized using $TeO_2$ nanorod templates for application to $H_2S$ gas sensors. $TeO_2$ nanorod templates were synthesized by using the VS method through thermal evaporation. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction showed that the synthesized nanotubes were monoclinic-structured polycrystalline CuO with diameter and wall thickness of approximately 100~300 nm and 5~10 nm, respectively. The CuO nanotube sensor showed responses of 136~325% for the $H_2S$ concentration of 0.1~5 ppm at room temperature. These response values are approximately twice as high as that of the CuO nanowire sensor for the same concentrations of $H_2S$ gas. Along with the investigation of the performance of the sensors, the mechanisms of $H_2S$ gas sensing of the CuO nanotubes are also discussed in this study.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1991.10a
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• pp.17-19
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• 1991

Pastes consisting of $CdZnS_{1-y}Te_{y}$ powder, 20wt/o of $CdCl_2$as a sintering aid and appropriate amount of Propylene Glycol(P.G) have been coated on glass substrates and were sintered at the temperature of $625^{\circ}C$ to find energy band gap, transmittance and electrical properties of the sintered films. The resistivity of sintered film increases with increasing Te content. X-ray diffraction patterns show that $CdZnS_{0.9}Te_{0.1}$ sintered film is in the single film in the two phase region. The transmittance of the sintered film decreases with increasing the Te content.

• Journal of the Korean Institute of Telematics and Electronics
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• v.12 no.2
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• pp.18-23
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• 1975

The dc conductivity, ac conductivity and switching effect of As.Te-Si.Ge have beon investigated. The dc conductivity ranged from $3{\times}10^{-7}{\Omega}^{-1}cm^{-1}$ to $1.5{\times}10^{-8}{\Omega}^{-1}cm^{-1}$ at room temperature and was found to be expressed by ${\sigma}$ = ${\sigma}_0$exp(-${\Delta}$E/kT) below the phase transition temperature Tg. The ac conductivity was much higher than dc conductivity and this result is consistent to experimental formula ${\sigma}$(w)=${\sigma}_0+Aw^n$. In the temperature range of 298$^{\circ}K$ ~ $473^{\circ}K$ the ac conductivity was independent of temperature at 200KHs. At lower frequencies the ac conductivity increased strong1y with temperature. Also, it has been found that all samples showed a threshold switching, but not a memory switching.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.158-158
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• 2003

수평 전기로에서 CuGaTe2 다결정을 합성하여 HWE 방법으로 CuGaTe2 단결정 박막을 반절연성 GaAs(100) 위에 성장하였다. CuGaTe2 단결정 박막은 증발원과 기판의 온도를 각각 67$0^{\circ}C$, 41$0^{\circ}C$로 성장하였다. 이때 단결정 박막의 결정성이 10K에서 측정한 광발광 스펙트럼은 954.5nm (1.2989eV) 근처에서 exciton emission 스펙트럼이 가장 강하게 나타났으며, 또한 이중결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)도 139arcsec로 가장 작게 측정되어 최적 성장 조건임을 알 수 있었다. Hall 효과는 van der Paw방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 8.72$\times$$10^{23}$개/㎥, 3.42$\times$$10^{-2}$$m^2$/V.s였다. 상온에서 CuGaTe2 단결정 박막의 광흡수 특성으로부터 에너지 띠간격이 1.22 eV였다 Band edge에 해당하는 광전도도peak의 온도 의존성은 Varshni 관계식으로 설명되었으며, Varshni 관계식의 상수값은 Eg(0) = 1.3982 eV, $\alpha$= 4.27$\times$$10^{-4}$ eV/K, $\beta$= 265.5 K로 주어졌다. CuGaTe2 단결정 박막의 광전류 단파장대 봉우리들로부터 10K에서 측정된 $\Delta$cr (crystal Field splitting)은 0.0791eV, $\Delta$s.o (spin orbit coupling)는 0.2463eV였다. 10K에서 광발광 봉우리의 919.8nm (1.3479eV)는 free exciton(Ex), 954.5nm (1.2989eV)는 donor-bound exciton 인 I2(DO,X)와 959.5nm (1.2921eV)는 acceptor-bound exciton 인 I1(AO,X) 이고, 964.6nm(1.2853eV)는 donor-acceptor pair(DAP) 발광, 1341.9nm (0.9239eV)는 self activated(SA)에 기인하는 광발광 봉우리로 고찰되었다.