• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1054-1056
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• 2002

High temperature Kermal diffusion from $POCl_3$ source usually used for conventional process through put of a cell manufacturing line and potentially reduce cell efficiency through bulk like time degradation. To fabricate high efficiency solar cells with minimal thermal processing, spin-on-doping(SOD) technique can be employed to emitter diffusion of a silicon solar cell. A technique is presented to emitter doping of a mono-crystalline solar cell using spin-on doping (SOD). Moreover it is shown that the sheet resistance variation with RTA temperature and time fer mono-crystalline and multi-crystalline silicon samples. This novel SOD technique was successfully used to produces 11.3% efficiency l04mm by 104mm size mono-crystalline silicon solar cells.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.219-220
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• 2000

We propose a new method for the formation of an aluminum parting layer in the fabrication of field emitter arrays, in which we used a reflow property of aluminum at a lower temperature than the deformation point of glass. After the sputtered aluminum layer on the gate metal was etched for the formation of gate holes, we carried out a rapid thermal annealing process, by which the aluminum slightly diffused into the gate hole. This reflowed aluminum could be used as a parting layer and emitter arrays were easily fabricated using this method.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.130-134
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• 2014

We have fabricated the selective emitter solar cell using double textured nanowires structure. The $40{\times}40mm2$-sized silicon substrates were textured to form the pyramid-shaped surface and the nanowires were fabricated by metal assisted chemical etching process using Ag nanoparticles, subsequently. The heavily doped and shallow emitters for selectiv eemitter solar cells were prepared through the thermal $POCl_3$ diffusion and chemical etch-back process, respectively. The front and rear electrodes were prepared following conventional screen printing method and the widths of fingers have been optimized. The selective emitter solar cell using double textured nanowires structure achieved a conversion efficiency of 17.9% with improved absorption and short circuit current density.

• Korean Journal of Materials Research
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• v.22 no.8
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• pp.390-396
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• 2012

Ag pastes added to Bi-oxide frits have been applied to the electrode material of Si solar cells. It has been reported that frits induce contacts between the Ag electrodes and the Si wafer after firing. During firing, the control of interfaces among Ag, the glass layer, and Si is one of the key factors for improving cell performance. Specifically, the thermo-physical properties of frits considerably influence Ag-Si contact. Therefore, the thermal properties of frits should be carefully controlled to enhance the efficiency of cells. In this study, the interface structures among Ag electrodes, glass layers, and recrystallites on an $n^+$ emitter were carefully analyzed with the thermal properties of lead-free frits. First, a cross-section of the area between the Ag electrodes and the Si wafer was studied in order to understand the interface structures in light of the thermal properties of the frits. The depth and area of the pits formed in the Si wafer were quantitatively calculated with the thermal properties of frits. The area of the glass layers between the Ag electrodes and Si, and the distribution of recrystallites on the $n^+$ emitter, were measured from a macroscopic point of view with the characteristics of the frits. Our studies suggest that the thermophysical properties should be controlled for the optimal performance of Si solar cells; our studies also show why cell performance deteriorated due to the high viscosity of frits in Ag pastes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.11
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• pp.1004-1009
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• 2012

Carbon nanotube are nanostructure with extraordinary field emission properties like high current density, low driving voltage and long time stability, because of their high electrical conductivity, high aspect ratio for geometrical field enhancement and superior thermal stability. But, there is some problem to mate metal and carbon nanotube, we have resolved this problem by using interfacial graphene. This approach takes advantage of superior electric and thermal conductivity between metal and carbon nanotube and shows superior performance compared to the existing field emitters. This result shows that such a carbon nanotube emitter in a stage where it can be used for Field Emission Electric Propulsion (FEEP).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.367-372
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• 2004

Two new extraction methods for the thermal Resistance of HBT(Heterojunction Bipolar Transistors) are proposed. First, the analytical expression, based on the thermal characteristics that the base to emitter junction voltage drops with the increase of junction temperature, is derived. Second, the thermal resistance equation that can predict the measured DC(Direct Current) data optimally is derived. These optimal thermal resistance expression is applied to the 2 finger 2${\times}$20${\mu}{\textrm}{m}$-AlGaAs/GaAs HBT and shows the good agreement with the measured data.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.12
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• pp.39-46
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• 1996

In AlGaAs/GaAs HBT the temperature dependence of DC parameters was investigated over the temperature range between 95K and 580K. The temperature dependence of DC parameters depends on the relative contribution of each of the current components suc as emitter-injection-current, base-injection-current, bulk recombination current, interface recombination curretn, thermal generation ecurrent and avalanche current due to impact ionization within the collector space charge layer in a specific temperature. In this paper we investigated the temperature effects on DC parameters such as V$_{BE,ON}$ current gain, input and output characteristics, V$_{CE, OFF}$, R$_{E}$, R$_{C}$ and analyzed the origins, and extracted the qualitativ econditions for a stable HBTs against the temperature variation. Finally, in order to keep HBTs stable with respect to the variation of temperature, the valance-band-energy-discontinuity at emitter-base heterojunction should be large enough to enhance the effect of carrier suppression at a relatively high temperature. In addition the recombination centers, especially around collector junction, should be removed and the area of emitter and collector junction should be identical as well.

• Mass Spectrometry Letters
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• v.15 no.1
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• pp.54-61
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• 2024

An improved voltage modulation method (VMM) was used to control the heat release and adsorption properties of the adsorbent. In this work, the voltage and flux modulation methods were considered under unified experimental conditions of dissociative surface ionization (SI) of polyatomic organic molecules, the criteria were found when under VMM conditions the current relaxation of SI carries information about the kinetic properties of thermal desorption of ionizable dissociation particles arriving on the surface of polyatomic molecules. Conditions were found under which the relaxation of the ionic current in the flux modulation method is determined by the kinetics of the heterogeneous dissociation reaction of the original polyatomic molecules. The values of the thermal desorption rate constant K⁺ and the activation energy E⁺ obtained with VMM for desorption of (CH₃)₂NCH⁺₂ ions with m/z 58 by adsorption of imipramine and amitriptyline molecules agree well with each other and with the results for the desorption of the same ions by adsorption of other molecules. This confirms one of the basic conditions for the equilibrium process SI - the a degree (β coefficient) of the same particles SI on the same emitter surface is the same and does not depend on the way these particles are formed on the emitter surface.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.81.1-81.1
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• 2015

최근 실리콘(Si) 원재료 가격의 하락으로 인하여, 태양광 시장에서 성능 좋은 저가의 태양광 모듈을 요구하고 있다. 즉, 와트(W)당 낮은 가격의 태양광 모듈을 선호하기 때문에 경쟁력을 갖추기 위하여서는 많은 출력을 낼 수 있는 고효율의 태양전지가 요구된다. 그래서 주목을 받고 있는 것이 N-type 실리콘 기판을 사용한 고효율 태양전지이다. 하지만, n-type Si 기판의 경우, pn 접합의 형성을 위하여서 기존의 열 확산(Thermal diffusion)법에 의한 에미터(Emitter) 형성방법은 양질의 pn접합을 형성하기에는 한계가 있다. 그로 인하여 주목하고 있는 기술이 반도체 공정에서 널리 사용되고 있는 이온 주입(Ion implantation)방식이다. 이 기술은 양질의 에미터 형성을 위하여, 동일한 양의 불순물(dopant) 주입, 정확한 접합 깊이 제어 등이 가능한 방법으로 고효율 태양전지 제작에 필수적이며, 가능한 기술이라고 할 수 있다. 본 발표에서는 어플라이드 머트리얼즈(Applied Materials)사가 보유하고 있는 고효율 태양전지 제작에 필수적인 이온주입방식의 기술과 양산화 가능한 관련장비 등을 소개 하고자 한다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.43-43
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• 2003

Carbon nanotubes(CNTs) have many application points, which are field emission devices, composites, hydrogen storage, nanodevices, supercapacitor and secondary battery. The most promising application point is emitter tip mays of field emission devices. Furthermore, it may be also useful as a vacuum device for high frequency and high power. But, there are some obstacles to fabricate carbon nanotube field emission device. One is that CNTs grown by CVD method has weak adhesion with substrate and the other is non-uniform length of them. These problems are very crucial in aging property and reliability of device in the field emission.