• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1341-1342
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• 2007

Poly-ether-sulphone (PES) 기판위에 열처리 공정을 거친 HgTe 나노입자를 이용하여 플렉시블 투명 박막 트랜지스터를 제작하였다. 활성층으로 사용된 HgTe 나노입자층은 UV/ozone 처리로 친수성화 된 PES 기판위에 스핀코팅으로 형성되었다. 제작된 박막 트랜지스터는 전형적인 p형 트랜지스터 특성을 보여주었으며, PES 기판에 스트레인을 가하지 않은 상태에서는 164의 전류점멸비와 1.6 $cm^{2}/Vs$ 의 전하 이동도가 계산되었고, PES 기판에 2.0%의 스트레인을 인가하였을 때에는 266의 전류점멸비와 1.0 $cm^2/Vs$ 의 전하 이동도가 계산되었다.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.67-74
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• 2018

Thermoelectric thin film devices of the in-plane configuration consisting of 8 pairs of n-type $Bi_2Te_3$ and p-type $Sb_2Te_3$ legs were processed on Si submounts by electrodeposition. The thermoelectric generation characteristics of the thin film devices were investigated with respect to the apparent temperature difference ${\Delta}T$ caused by LED lighting as well as the change of the leg thickness. When ${\Delta}T$ was 7.4 K, the open circuit voltages of 6.1 mV, 7.4 mV, and 11.8 mV and the maximum output powers of 6.6 nW, 12.8 nW, and 41.9 nW were measured for the devices with the thermoelectric legs of which thickness were $2.5{\mu}m$, $5{\mu}m$, and $10{\mu}m$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.84-85
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• 2009

The single crystals of p-$CdIn_2Te_4$ were grown by the Bridgman method without the seed crystal. From photocurrent measurements, it was found that three peaks, A, B, and C, correspond to the intrinsic transition from the valence band states of $\Gamma_7(A)$, $\Gamma_6(B)$, and $\Gamma_7(C)$ to the conduction band state of $\Gamma_6$, respectively. The crystal field splitting and the spin orbit splitting were found to be 0.2360 and 0.1119 eV, respectively, from the photocurrent spectroscopy. The temperature dependence of the $CdIn_2Te_4$ band gap energy was given by the equation of $E_g(T)=E_g(0)$ - $(9.43\times10^{-3})T^2$/(2676+T). $E_g(0)$ was estimated to be 1.4750, 1.7110, and 1.8229 eV at the valence band states of A, B, and C, respectively. The band gap energy of $p-CdIn_2Te_4$ at room temperature was determined to be 1.2023 eV.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.731-739
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• 2012

Transverse electric modes in parallel plate waveguide of which cut-off frequency is much lower than that of $TE_1$ and $TM_1$ mode generally known as the lowest higher order mode are investigated. Electric and magnetic field components of the modes are evaluated with the assumption that boundaries at both sides are perfect magnetic conductor. The existence of these modes are verified by simulation and experimental measurement of parallel plate waveguide cavity. Changed characteristics from the fact that the boundaries are imperfect are studied.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.138-139
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• 2006

Metal organic chemical vapor deposition has been investigated for growth of $Sb_{2-x}Bi_xTe_3$ films on (001) GaAs substrates using diisopropyltelluride, triethylantimony and trimethylbismuth as metal organic sources. The thermoelectric properties were measured at room temperature and include Seebeck coefficient, electrical conductivity and Hall effect. In-plane carrier concentration and electrical Hall mobility were highly dependent on precursor's composition ratio and deposition temperature. The thermoelectric Power factor($={\alpha}^2{\sigma}$) was calculated from theses properties. The best Power factor was $2.6\;{\times}\;10^{-3}W/mK^2$, given by grown $Sb_{1.6}Bi_{0.4}Te_3$ at $450^{\circ}C$. These materials could potentially be incorporated into advanced thermoelectric unicouples for a variety of power generation applications.

• Transactions on Electrical and Electronic Materials
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• v.9 no.6
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• pp.223-226
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• 2008

$Ge_1Se_1Te_2$ chalcogenide amorphous materials was prepared by the conventional melt-quenching method. Samples were processed bye-beam evaporator systems and RF-sputtering systems. Phase change characteristics were analyzed by measuring glassification temperature, crystallization temperature and density of bulk material. The thermal characteristics were measured at the temperature between 300 K and 700 K, and the electrical characteristics were studied within the range from 0 V to 3 V. The obtained results agree with the electrothermal model for Phase-Change Random Access Memory.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.4
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• pp.149-152
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• 2002

We performed the modeling of the dielectric functions of C $d_{0.77}$M $g_{0.23}$Te by using parametric semiconductor model. Parametric model describes the analytic dielectric function as the summation of several energy-bounded Gaussian-broadened polynomials and provides a reasonably well parameterized function which can accurately reproduce the optical constants of semiconductor materials. We obtained the values of fitting parameters of the Mg composition 0.23 in the parametric model. From these parameters we could remove interference oscillations to obtain the dielectric function of C $d_{0.77}$M $g_{0.23}$Te alloy film for full 0.5-6.0 eV energy range.y range.

• 전기의세계
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• v.23 no.6
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• pp.49-55
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• 1974

Amorphous semiconductor from As 30 Te 48 Ge 10 Si 12 was prepared, and studied electron microscopy, X-ray analysis and resistivity measurement. It's resistivity is 1.56*10$^{6}$ .ohm.-cm when small ampule is used for preparing sample it is found that no phase separation has occurced by electron microscopy, and that phase transition temperature is 232.deg. C by differential Thermal Analysis. The specimen showed threshold switching that the low resistance state occur at critical electric field and the resistance recover at low applied field. Critical electric field of the switching is 10$^{5}$ V/cm at room temperature. Threshold voltage secreace exponentially with increasing ambient temperature and at that each voltage resistance of the switching device increase exponentially. According to the series resistance and applied vottage current slope on the V-I curve is varied. When applied voltage is decreased after switching, the resistance of the switching device is increased. By this result the origin of the switching is the Joule's heating.

• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.401-407
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• 2011

The purpose of this study is to know the differences of MR spectra, obtained from normal volunteers by variable TE value, through the quantitative analysis of brain metabolites by peak integral and SNR between 1.5T and 3.0T, together with PRESS and STEAM pulse sequence. Single-voxel MR proton spectra of the human brain obtained from normal volunteers at both 3.0T MR system (Magnetom Trio, SIEMENS, Germany) and 1.5T MR system (Signa Twinspeed, GE, USA) using the STEAM and PRESS pulse sequence. 10 healthy volunteers (3.0T:3 males, 2 females; 1.5T : 3 males, 2 females) with the range from 22 to 30 years old (mean 26 years) participated in our study. They had no personal or familial history of neurological diseases and had a normal neurological examination. Data acquisition parameters were closely matched between the two field strengths. Spectra were recorded in the white matter of the occipital lobe. Spectra were compared in terms of resolution and signal-to-noise ratio(SNR), and echo time(TE) were estimated at both field strengths. Imaging parameters was used for acquisition of the proton spectrum were as follow : TR 2000msec, TE 30ms, 40ms, 50ms, 60ms, 90ms, 144ms, 288ms, NA=96, VOI=$20{\times}20{\times}20mm3$. As the echo times were increased, the spectra obtained from 3.0T and 1.5T show decreased peak integral and SNR at both pulse sequence. PRESS pulse sequence shows higher SNR and signal intensity than those of STEAM. Especially, Spectra in normal volunteers at 3.0T demonstrated significantly improved overall SNR and spectral resolution compared to 1.5T(Fig1). The spectra acquired at short echo time, 3T MR system shows a twice improvement in SNR compared to 1.5T MR system(Table. 1). But, there was no significant difference between 3.0Tand 1.5T at long TE It is concluded that PRESS and short TE is useful for quantification of the brain metabolites at 3.0T MRS, our standardized protocol for quantification of the brain metabolites at 3.0T MRS is useful to evaluate the brain diseases by monitoring the systematic changes of biochemical metabolites concentration in vivo.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.04a
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• pp.33-34
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• 2006