Gye-Choon Park

Electrical and optical properties of ZnO thin film as a function of deposition parameters

Al-doped zinc oxide (AZO) and undoped zinc oxide (ZO) films have been prepared by rf magnetron sputtering. Films with low resistivities were achieved by using an Al-doped ZnO target and films with higher resistivities can be obtained by introducing oxygen during deposition. An AZO thin film which was fabricated with an rf power of 180W, a sputtering pressure of 10 m Torr and thickness of 5000 A showed the lowest resistivity of 1.4 x 10 -4 Ωcm and transmittance of 95% in the visible range, and ZO film made by reactive sputtering with the above 10% oxygen content had the highest resistivity of 6×10 14 Ωcm.

Electrochemical properties of carbon composite electrode with polymer electrolyte for electric double-layer capacitor

Abstract The purpose of this study is to research and develop carbon composites for this electric double-layer capacitor (EDLC) film. We investigated cyclic voltammetry, ac impedance response, leakage current and charge/discharge cycling of carbon composite electrodes in polymer electrolyte. The radius of the AC electrode semicircle adding 5 wt.% KS-6 was very small compared with that of the AC electrode alone. The discharge capacitance of the AC composite with 5 wt.% KS-6 in the 1st and 10th cycles was 100 and 94 mF cm −2 , respectively, at a current density of 0.1 mA cm −2 . At the 1000th cycling, the highest specific capacitance, 4.3 F g −1 , was measured for an activated carbon composite with 5 wt.% KS-6 in PVDF–PC–EC–LiC1O 4 electrolyte. The carbon composite electrode performed with good cycliability over 1000 cycles and with 100% coulombic efficiency.

E-beam deposited Ag-nanoparticles plasmonic organic solar cell and its absorption enhancement analysis using FDTD-based cylindrical nano-particle optical model

We report the plasmon-assisted photocurrent enhancement in Ag-nanoparticles (Ag-NPs) embedded PEDOT:PSS/P3HT:PCBM organic solar cells, and systematically investigate the causes of the improved optical absorption based on a cylindrical Ag-NPs optical model which is simulated with a 3-Dimensional finite difference time domain (FDTD) method. The proposed cylindrical Ag-NPs optical model is able to explain the optical absorption enhancement by the localized surface plasmon resonance (LSPR) modes, and to provide a further understanding of Ag-NPs shape parameters which play an important role to determine the broadband absorption phenomena in plasmonic organic solar cells. A significant increase in the power conversion efficiency (PCE) of the plasmonic solar cell was experimentally observed and compared with that of the solar cells without Ag-NPs. Finally, our conclusion was made after briefly discussing the electrical effects of the fabricated plasmonic organic solar cells.

Photovoltaic characteristics of CuInS2CdS solar cell by electron beam evaporation

When a CuInS2CdS solar cell was fabricated by depositing CdS thin film with dopant In of 1.0 at% on ternary compound CuInS2 thin film with the lowest resistivity of 5.59 × 10−2 Ωcm, its best result was as follows: Voc = 461 mV, Isc = 26.9 mA, FF = 0.685, η = 5.66% under the illumination of 100 mW/cm2. And its series resistance and lattice mismatch was 5.1 Ω and 3.2%, respectively. Besides, a 4 layer structure solar cell of ϱ-CuInS2/high ϱ-CuInS2/high ϱ-CdS/low ϱ - CdS has been fabricated. When thickness of high ϱ - CuInS2 was 0.2 μm, its best result was as follows: Voc = 580 mV, Isc = 30.6 mA, FF = 0.697, η = 8.25%. An its series resistance and lattice mismatch were 4.3 Ω and 2.8%, respectively.

A Study on the Properties of MgF 2 Antireflection Film for Solar Cells

MgF2 is a current material used for optical applications in the ultraviolet and deep ultraviolet range. Process variables for manufacturing MgF2 thin film were established in order to clarify the optimum conditions for the growth of the thin film, dependant upon the process conditions, and then by changing a number of the vapor deposition conditions, substrate temperatures, and heat treatment conditions, the structural and optical characteristics were measured. Then, optimum process variables were thus derived. Nevertheless, modern applications still require improvement in the optical and structural quality of the deposited layers. In the present work, in order to understand the composition and microstructure of MgF2, single layers grown on a slide glass substrate using an Electron beam Evaporator (KV‐ 660), were analyzed and compared. The surface substrate temperature, having an effect on the quality of the thin film, was changed from 200°C to 350°C at intervals of 50°C. The heat treatment temperature, which also has an effect on the thin film, was changed from 200°C to 400°C at intervals of 50°C. The physical properties of the thin film were investigated at various fabrication conditions, such as the substrate temperature, the heat treatment temperature, and the heat treatment time, by X‐ray diffraction, and field emission‐scanning electron microscopy.

Electro-optic phase modulator using metal-defined polymer optical waveguide

We demonstrate metal-defined electro-optic polymer phase modulators for the first time. A metal strip patterned on top of a three-layer slab waveguide causes a strain-induced refractive index change, resulting in lateral optical mode confinement within the core layer. The strain profile, refractive indexes, and optical mode shapes of the metal defined optical waveguide are obtained analytically. Electro-optic phase modulators fabricated using this technique have a driving voltage of 5.6V, and ∼18dB of extinction ratio at 1.55μm wavelength. These results may be used in the complex design of integrated polymer optical circuits that require a simple and cheap fabrication process.

A Study of the Properties of CuInS 2 Thin Film by Sulfurization

The copper indium disulfide (CuInS 2) thin film was manufactured using sputtering and thermal evaporation methods, and the annealing with sulfurization process was used in the vacuum chamber to the substrate temperature on the glass substrate, the annealing temperature and the composition ratio, and the characteristics thereof were investigated. The CuInS2 thin film was manufactured by the sulfurization of a soda lime glass (SLG) Cu/In/S stacked (1) elemental layer deposited on a glass substrate by vacuum chamber annealing (2) with sulfurization for various times at a temperature of substrate temperature of 200°C. The structure and electrical properties of the film was measured in order to determine the optimum conditions for the growth of CuInS2 ternary compound semiconductor CuInS2 thin films with a non-stoichiometric composition. The physical properties of the thin film were investigated under various fabrication conditions (3,4), including the substrate temperature, annealing temperature and annealing time by X-ray diffraction (XRD), field Emission scanning electron microscope (FE-SEM), and Hall measurement systems. (5) The sputtering rate depending upon the DC/RF power was controlled so that the composition ratio of Cu versus In might be around 1:1, and the substrate temperature affecting the quality of the film was varied in the range of room temperature (RT) to 300°C at intervals of 100°C, and the annealing temperature of the thin film was varied RT to 550°C in intervals of 100°C.

A Study on Properties of CuInSe 2 Thin Films by Substrate Temperature and Annealing Temperature

Process variables for manufacturing the thin film were established in order to clarify optimum conditions for growth of the thin film depending upon process conditions (substrate temperature, sputtering pressure, DC/RF Power), and then by changing a number of vapor deposition conditions and Annealing conditions variously, structural and electrical characteristics were measured. Thereby, optimum process variables were derived. For the manufacture of the , Cu, In and Se were vapor-deposited in the named order. Among them, Cu and In were vapor-deposited by using the sputtering method in consideration of their adhesive force to the substrate, and the DC/RF power was controlled so that the composition of Cu and In might be 1 : 1, while the surface temperature having an effect on the quality of the thin film was changed from at intervals of . The diffract fringe of X-ray, which depended upon the substrate temperature and the Annealing temperature of the manufactured thin film, was investigated. scanning electron microgaphs of represents a case that a sample manufactured at the substrate temperature of was thermally treated at . As a result, at of the Annealing temperature, their chemical composition was measured in the proportion of 1 : 1 : 2. It could be known that under this condition, the most excellent thin film was formed, compared with the other conditions.

A Study on Properties of Al:ZnO Thin Films by Used RTP Method

Copyright 2013 KIEEME. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. A Study on Properties of Al:ZnO Thin Films by Used RTP Method

Plasmonic organic solar cell and its absorption enhancement analysis using cylindrical Ag nano-particle model based on finite difference time domain (FDTD)

We report the plasmon-assisted photocurrent enhancement in Ag nanoparticles (NPs)-embedded PEDOT:PSS/P3HT:PCBM organic solar cells, and theoretically investigate the causes of the improved optical absorption based on a cylindrical Ag-NPs model which is simulated with a finite difference time domain (FDTD) method. The proposed cylindrical Ag-NPs model is able to explain the optical absorption enhancement by the localized surface plasmon resonance (LSPR) modes, and to provide a further understanding of Ag-NPs shape parameters which play an important role to determine the broadband absorption phenomena in plasmonic organic solar cells.