Minimizing the carrier recombination and electrical loss through surface passivation is required for high efficiency c-Si solar cell. Usually, SiN_{X}, SiO_{X}, SiON_{X} and AlO_{X} layers are used as passivation layer in solar cell application. Silicon oxide layer is one of the good passivation layer in Si based solar cell application. It has good selective carrier, low interface state density, good thermal stability and tunneling effect. Recently tunneling based passivation layer is used for high efficiency Si solar cell such as HIT, TOPCon and TRIEX structure. In this paper, we focused on silicon oxide grown by various the method (thermal, wet-chemical, plasma) and passivation effect in c-Si solar cell.

Resistive random access memory (ReRAM) of metallic conduction channel mechanism is based on the electrochemical control of metal in solid electrolyte thin film. Amorphous chalcogenide materials have the solid electrolyte characteristic and optical reactivity at the same time. The optical reactivity has been used to improve the memory switching characteristics of the amorphous As2Se3-based ReRAM. This study focuses on the formation of holographic lattices patterns in the amorphous As2Se3 thin film for straight conductive channel. The optical parameters of amorphous As2Se3 thin film which is a refractive index and extinction coefficient was taken by n&k thin film analyzer. He-Cd laser (wavelength: 325 nm) was selected based on these basic optical parameters. The straighten conduction channel was formed by holographic lithography method using He-Cd laser. Ag+ ions that photo-diffused periodically by holographic lithography method will be the role of straight channel patterns. The fabricated ReRAM operated more less voltage and indicated better reliability.

In this study, in order to develop the composition ceramics for ultrasonic sensor with high d33*g33, (Pb1-3x/2Bix(Mg1/2W1/2)0.03(Ni1/3Nb2/3)0.09(Zr0.5Ti0.5)0.88O3)(PMW-PNN-PZT) system ceramics were prepared using CuO as sintering aids. And then, their microstructure, piezoelectric and dielectric characteristics were systemetically investigated with bismuth substitution. The PMW-PNN-PZT ceramic specimens could be sintered at sintering temperature of 940℃ by adding sintering aids. At x=0.015 specimen, the density, electromechanical coupling factor(kp), dielectric constant, piezoelectric constant(d33) and piezoelectric figure of merit(d33*g33) indicated the optimal properties of 7.90 g/cm3, 0.67, 2,511, 628 pC/N, and 17.7 pm2/N, respectively, for duplex ultrasonic sensor application.

In this study, Ni0.79(Mn2.21-χCuχ)O4 (x=0~0.25) specimens were prepared by using a conventional mixed oxide method. All specimens were sintered in air at 1,℃ for 12 h and cooled at a rate of 2℃/min to 800℃, subsequently quenching to room temperature. We investigated the structural and electrical properties of Ni 0.79(Mn2,21-χCuχ)O4 specimens with variation of CuO amount for the application of NTC thermistors. As results of X-ray diffraction patterns, all specimens showed the formation of a complete solid solution with cubic spinel phase. The relationship between ln ρ and the reciprocal of absolute temperature(1/T) for the NTC thermistors was shown linearity, which exhibited the typical NTC thermistor properties. With increasing the amount of CuO, resistivity at room temperature, B-value, and temperature coefficient resistance decreased.

We investigated the effect of Bi1/2(Na0.82K0.18)1/2TiO3 (BNKT) modification on the ferroelectric and electric-field-induced strain (EFIS) properties of lead-free 0.97Bi1/2(Na0.82K0.18)1/2TiO3-0.03LaFeO3 (BNKTLF) ceramics as a function of BNKT content (x= 0, 0.1, 0.2, 0.3, 0.5, and 1). BNKT-modified BNKTLF powders were synthesized using a conventional solid-state reaction method. As the BNKT content x increased from 0 to 1 the normalized electric-field-induced strain (S_{max}/E_{max}) was observed to increase at relatively low fields, i.e., below the poling field. Moreover, BNKTLF-30BNKT showed about 460 pm/V as low as at 3 kV/mm, which is a considerably high value among the lead-free systems reported so far. Consequently, it was confirmed that ceramic-ceramic composite, a mixture of an ergodic relaxor matrix and embedded ferroelectric seeds, is a salient way to make lead-free piezoelectrics practical with enhanced EFIS at low field as well as less hysterical.

In this paper, GaN film was grown on AlN/PSS by hydride vapor phase epitaxy compared with GaN on planar sapphire. Thin AlN layer for buffer layer was deposited on patterned sapphire substrate (PSS) by metal organic chemical vapor deposition. Surface roughness of GaN/AlN on PSS was remarkably decreased from 28.31 to 5.53 nm. Transmittance of GaN/AlN grown on PSS was lower than that of planar sapphire at entire range. XRD spectra of GaN/AlN grown on PSS corresponded the wurzite structure and c-axis oriented. The full width at half maximum (FWHM) values of ω-scan X-ray rocking curve (XRC) for GaN/AlN grown on PSS were 196 and 208 arcsec for symmetric (0 0 2) and asymmetric (1 0 2), respectively. FWHM of GaN on AlN/PSS was improved more than 50% because of lateral overgrowth and AlN buffer effect.

In this paper, we have studied about the optimum fabrication condition of the printed Indium Tin Oxide (ITO) layers for the electrical resistance-type sensor application. We have investigated on the substrates surface treatments, mixing ratio of organic binder/ITO powder, and viscosity of the printing paste to determine the optimum condition of the screen printed ITO layer. Also, we found that the printing condition is closely related with the sensor performance. To know the feasibility of printed ITO layer as an electrical resistance-type sensor, we have fabricated the ITO sensors with a printed and sputtered ITO layers. The printed ITO films revealed 102 times higher sensitivity than the sputtered ITO layer. Also, the sputtered ITO layer exhibited an operating temperature of 127℃ at the operating voltage of 5 V. While, in case of the printed ITO layer showed the operating temperature of 27.6℃ in high operating voltage of 30 V. We found that the printed ITO layer is suitable for the various sensor applications.

NiO serves as a window layer for Si photoelectric devices. Due to the wide energy bandgap of NiO, high optical transparency (over 80%) was achieved and applied for Si photoelectric devices. Due to the high the high mobility, the heterojunction device (Al/n-Si/SiO2/p-NiO/ITO) provide ultimately fast photoresponses of rising time of 38.33 μs and falling time of 39.25 μs, respectively. This functional NiO layer would provide benefits for high-performing photoelectric devices, including photodetectors and solar cells.

In this paper, we fabricated Cu/Mn alloy shunt resistor with low resistance and thermal stability for use of mobile electronic devices. We designed metal alloy composed of copper (Cu) and manganese (Mn) to embody in low resistance and low TCR which are conflict each other. Cu allows high electrical conductivity and Mn serves thermal stability in this Cu/Mn alloy system. We confirmed the elemental composition of the designed metal alloy system by using energy dispersive X-ray (EDX) analysis. We obtained low resistance below 10 mΩ and low temperature coefficient of resistance (TCR) below 100 ppm/℃ from the designed Cu/Mn alloy resistor. And in order to minimize resistance change caused by alternative frequency on circuit, shape design of the metal alloy wire is performed by rolling process. Finally, we conclude that design of the metal alloy system was successfully done by alloying Cu and 3 wt% of Mn, and the Cu/Mn alloy resistor has low resistance and thermal stability.

In this paper, we investigated the electrical properties of crystalline silicon solar cell fabricated with Ni/Cu/Ag plating. The laser process was used to ablate silicon nitride layer as well as to form the selective emitter. Phosphoric acid layer was spin-coated to prevent damage caused by laser and formed selective emitter during laser process. As a result, the contact resistance was decreased by lower sheet resistance in electrode region. Low sheet resistance was obtained by increasing laser current, but efficiency and open circuit voltage were decreased by damage on the wafer surface. KOH treatment was used to remove the laser damage on the silicon surface prior to metalization of the front electrode by Ni/Cu/Ag plating. Ni and Cu were plated for each 4 minutes and 16 minutes and very thin layer of Ag with 1 ㎛ thickness was plated onto Ni/Cu electrode for 30 seconds to prevent oxidation of the electrode. The silicon solar cells with KOH treatment showed the 0.2% improved efficiency compared to those without treatment.

In this paper, the efficiency improvement of the heterojunction with intrinsic thin layer (HIT) solar cells is obtained by optimization process of p-type a-SiC:H as emitter. The optoelectronic of p-type a-SiC:H layers including the optical band-gap and conductivity under the methane gas content variation is conducted in detail. A significant increase in the Jsc by 1 mA/cm2 and Voc by 30 mV are attributed to enhanced photon-absorption due to broader band-gap of p-a-SiC:H and reduced band-offsets at p-side interface, respectively of HIT solar cells.

Thermal characteristics of 20 W LED module on light thermal conductive plastic (TCP) heat sink were investigated in comparison with that on aluminum die casting alloy (ADC-12). Thermal simulations of the heat sinks were conducted by using flow simulation of SolidWorks with the following input parameters: density is 1.70 and 2.82 kg/㎡, thermal conductivity is 20 and 92 W/(m·K) for TCP and ADC-12, respectively. The simulated and measured temperatures of the LED modules on TCP heat sink were consistent with its measured temperature, which was 3℃ higher that on ADC-12. The fabricated LED module on TCP heat sink with a weight of 120.5 g was 30% lighter in weight than that of the ADC-12 reference with 171.0 g.