• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.691-692
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• 2011

• Korean Journal of Materials Research
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• v.15 no.2
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• pp.89-92
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• 2005

The induction melting was employed to prepare Nb-doped $CoSb_3$ skutterudites and their thermoelectric properties were investigated. Single phase $\delta-CoSb_3$ was successfully obtained by induction melting and subsequent annealing at $400^{\circ}C$ for 2 hrs in vacuum. The positive signs of Seebeck coefficients for all the specimens revealed that Nb atoms acted as p-type dopants by substituting Co atoms. Electrical conductivity decreased and then increased with increasing temperature, indicating mixed conduction behavior. Electrical conductivity increased by Nb doping, and it was saturated at high temperature. Maximum value of the thermoelectric power factor was shifted to higher temperature with increasing the amount of Nb doping, mainly originated from the high Seebeck coefficient around mixed conduction temperature and high electrical conductivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.403-406
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• 2000

The piezoelectric properties and the doping effect of N $b_2$ $O_{5}$ and Mn $O_2$for 0.95PbZ $r_{x}$ $Ti_{x}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$ compositions have been investigated. In the composition of 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.05Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$the Values Of $k_{p}$ find and $\varepsilon$$_{33}$ $^{T}$ are maximized, but $Q_{m}$ Was minimized ( $k_{p}$ =0.51, $Q_{m}$ =1750). The grain size was suppressed and the uniformity of grain was improved with doping concentration of N $b_2$ $O_{5}$ for 0.95PbZ $r_{0.54}$ $Ti_{0.46}$ $O_3$+0.005Pb(M $n_{0.42}$ $W_{0.26}$S $b_{0.32}$) $O_3$sample. The values of $k_{p}$ increased and the values of $Q_{m}$ slightly decreased when 0.5 wt% of N $b_2$ $O_{5}$ is doped. And the values of $k_{p}$ was the same formation of the N $b_2$ $O_{5}$ dopant when 0.5 wt% of M $n_2$ $O_{5}$ is doped. But the values of $Q_{m}$ was deeply decreased when 0.5 wt% of Mn $O_2$is doped. As a experiment results under high electric field driving, this piezoelectric ceramics are very stable. Conclusively, piezoelectric ceramic compsiton investigated at this paper is suitable for application to high power piezoelectric devices.. devices..ices.. devices..

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.168-168
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• 2012

본 연구에서는 Molybdenum oxide (MoOx)-doped 4,4',4"-tris[2-naphthyl(amino)] triphenylamine(2-TNATA)의 P-doping에 의한 hole ohmic contact과 fullerene (C60)/lithium (LiF)의 electron ohmic contact에 의한 All Ohmic contact를 이용한 유기 발광 다이오드 (OLEDs)의 광저항 특성의 향상을 설명한다. 이 소자의 성능은 MoOx-doped 2-TNATA의 두께와 도핑농도에 큰 영향을 받는다. glass/ITO/MoOx-doped 2-TNATA (100 nm)/Al 구조의 소자에서 MoOx-doped 2-TNATA 도핑 농도가 25%에서 75%로 증가할수록 hole only device의 hole ohmic 특성이 향상됐다. 그 이유는 p-type doping effect 때문이다. 또한 photoemission spectra 분석결과, p-type doping effect는 hole-injecting barrier 높이는 낮추고, hole conductivity는 향상되었다. 이것은 2-TNATA에 도핑된 MoOx의 전하전송 콤플렉스의 형성으로 hole carrier의 수가 증가하여 발생되었다. MoOx-doped 2-TNATA의 hole ohmic contact과 fullerene (C60)/lithium fluoride (LiF)의 electron ohmic contact 으로 구성된 glass/ITO/MoOx-doped 2-TNATA (75%, 60 nm)/NPB (10 nm)/Alq3 (35 nm)/C60 (5 nm)/LiF (1 nm)/Al (150 nm)의 소자구조는 6,4V에서 127,600 cd/m2 최대 휘도와 약 1,000 cd/m2에서 4.7 lm/W의 높은 전력 효율을 보여준다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.394-399
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• 1998

High power characteristics with vibration velocity were studied in $Pb(Y_{2/3}W_{1/3})O_3-Pb(Zr,Ti)O_3$(PYW-PZT) ceramics by using the constant current method. Young s modulus $Y_0^E$ and mechanical quality factor $Q_m$ are a function of the square of effective vibration velocity \upsilon_0$. The nonlinear proportional constants of the above functions indicate the degree of stability under the vibration level change. The stability of PYW-PZT ceramics estimated by these constants coincides with the results obtained through the heat generation. It was found that $Q_m$ was markedly decreased with increasing the vibration velocity, accompanying a lot of heat generation. The vibration hysteresis and dielectric loss according to the vibration velocity was reduced by doping $Fe_2O_3$to the ceramics. On the contrary, these losses was increased by doping $Nb_2O_5$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.195-196
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• 2008

Doping depth, doping concentration, and resistivity of crystalline silicon solar cell are variables which take important portion in cell's efficiency. To get highly efficient solar cell, PC1D is used to calculate $I_{sc}$, $V_{oc}$, and $P_{max}$. Depth factor, peak doping, and base resistivity was used as variables. As a result, the optimized value of emitter peak doping is $1\times10^{19}cm^{-3}$, depth factor is $1{\mu}m$, and base $\rho$ is $ 0.1\Omega$-cm. Under the optimized condition, the solar cell gets efficiency 19.03(%).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.322-322
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• 2010

For boron doping on n-type silicon wafer, around $1,000^{\circ}C$ doping temperature is required, because of the relatively low solubility of boron in a crystalline silicon comparing to the phosphorus case. Boron doping by fiber laser annealing and lamp furnace heat treatment were carried out for the uniformly deposited p-a-Si:H layer. Since the uniformly deposited p-a-Si:H layer by cluster is highly needed to be doped with high temperature heat treatment. Amorphous silicon layer absorption range for fiber laser did not match well to be directly annealed. To improve the annealing effect, we introduce additional lamp furnace heat treatment. For p-a-Si:H layer with the ratio of $SiH_4:B_2H_6:H_2$=30:30:120, at $200^{\circ}C$, 50 W power, 0.2 Torr for 30 min. $20\;mm\;{\times}\;20\;mm$ size fiber laser cut wafers were activated by Q-switched fiber laser (1,064 nm) with different sets of power levels and periods, and for the lamp furnace annealing, $980^{\circ}C$ for 30 min heat treatment were implemented. To make the sheet resistance expectable and uniform as important processes for the $p^+$ layer on a polished n-type silicon wafer of (100) plane, the Q-switched fiber laser used. In consequence of comparing the results of lifetime measurement and sheet resistance relation, the fiber laser treatment showed the trade-offs between the lifetime and the sheet resistance as $100\;{\omega}/sq.$ and $11.8\;{\mu}s$ vs. $17\;{\omega}/sq.$ and $8.2\;{\mu}s$. Diode level device was made to confirm the electrical properties of these experimental results by measuring C-V(-F), I-V(-T) characteristics. Uniform and expectable boron heavy doped layers by fiber laser and lamp furnace are not only basic and essential conditions for the n-type crystalline silicon solar cell fabrication processes, but also the controllable doping concentration and depth can be established according to the deposition conditions of layers.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.248-249
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• 2014

본 연구에서는 GZO:Sn에서 Sn의 함유량에 따른 트랜지스터 특성 변화를 알아보았다. 그 결과 GZO:Sn=200W:9W 의 소자에서 가장 좋은 트랜지스터 특성을 얻을 수 있었다.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.193.1-193.1
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2015.11a
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• pp.179-179
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• 2015