• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.283-290
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• 1999

The $n^+/p/p^+$ junction PERL solar cell of $0.1{\sim}2{\Omega}{\cdot}cm$ (100) p type silicon wafer was fabricated through the following steps; that is, wafer cutting, inverted pyramidally textured surfaces etching by KOH, phosphorus and boron diffusion, anti-reflection coating, grid formation and contact annealing. At this time, the optical characteristics of device surface and the efficiency of doping concentration for resistivity were investigated. And diffusion depth and doping concentration for n+ doping were simulated by silvaco program. Then their results were compared with measured results. Under the illumination of AM (air mass)1.5, $100\;mW/cm^2$ $I_{sc}$, $V_{oc}$, fill factor and the conversion efficiency were 43mA, 0.6 V, 0.62. and 16% respectively.

• Resources Recycling
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• v.22 no.4
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• pp.38-45
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• 2013

The porous ceramic beads using mine tailing were prepared and applied to catalytic converter for NOx/SOx removal. Catalytic support was used synthesized mesoporous silica (SBA-15) which coated on surface. Internal structure for porous ceramic beads was composed of three-dimensional network structure and porosity was about 80%. In addition, the specific surface area for mesoporous silica(SBA-15) coated on converter was significantly increased 55 $m^2/g$ compared with 0.8 $m^2/g$ before coating. NOx/SOx removal experiment was performed using $V_2O_5$ and $V_2O_5$/CuO converter. NOx conversion ratio for $V_2O_5$/CuO converter was approximately increased 10% compared to $V_2O_5$ converter. In addition, catalytic converter of $V_2O_5$/CuO was shown to remove 95% of NOx and 90% of SOx at reaction temperature of $350^{\circ}C$, space velocity of 10000 $h^{-1}$ and $O_2$ concentrations of 5%, respectively.

• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.688-693
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• 2014

For investigating NO reduction activity of an catalytic filter, the catalytic performance was measured under the presence of $SO_2$ and $H_2O$, respectively or simultaneously in the simulation gas composed of NO, $NH_3$, and air. The catalytic filter was prepared by coating $V_2O_5-WO_3/TiO_2$ catalyst on the pore surface of SiC filter element of which the superior performance for the particulate removal was well known. At the temperature below $260^{\circ}C$, the catalytic activities were enormously decreased under the presence of $SO_2$ and $H_2O$, respectively or simultaneously, compared with those under the cases of the absence of $SO_2$ and $H_2O$. However, the presence of $SO_2$ promoted the performance of the catalytic filter above $320^{\circ}C$ with showing the NO conversion better than 99.8% for the NO inlet concentration of 500 ppm and at the face velocity of 2 cm/s. In particular, the presence of water showed high NO conversion higher than 99% up to high temperature of $380^{\circ}C$. This effect of water was explained by the reason that it retarded the ammonia oxidation which is the main step into the formation of $N_2O$. The initial NO reduction activity of the catalytic filter maintained for the duration of 100 hours in the presence of $SO_2$ and $H_2O$. Therefore, it was concluded that the catalytic filter was promisingly useful for the industrial NOx reduction catalyst in order to treat the particulate and NO simultaneously.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.113-117
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• 2016

Recently, hydrogen is regarded as important energy in the future, because it is clean and renewable. The photoelectrochemical (PEC) system, which produce hydrogen using water splitting by solar energy, is one of the most promising energy systems because it has abundant energy sources and good theoretical efficiency. GaN has recently been regarded as suitable photoelectrode that could be used to split water to generate hydrogen without extra bias because its band edge position include water redox potential ($V_{redox}=1.23$ vs. SHE). GaN also shows considerable corrosion resistance in aqueous solutions and it is possible to control its properties, such as structure, band gap, and catalyst characteristics, in order to improve solar energy conversion efficiency. But, even if the band edge position of GaN make PEC reaction facilitate without bias, the overpotential of oxygen evolution reaction could reduce the efficiency of system. One of the ways to decrease overpotential is introduction of co-catalyst on photoelectrode. In this paper, we will investigate the effect of manganese dioxide ($MnO_2$) as a co-catalyst. $MnO_2$ particles were dispersed on GaN photoelectrode by spincoater and analyzed properties of the PEC system using potentiostat (PARSTAT4000). After coating $MnO_2$, the flat-band potential ($V_{fb}$) and the onset voltage ($V_{onset}$) were moved negatively by 0.195 V and 0.116 V, respectively. The photocurrent density increased on $MnO_2$ coated sample and time dependence was also improved. These results showed $MnO_2$ has an effect as a co-catalyst and it would enhance the efficiency of overall PEC system.