Woojin Park

Doping Cu into silver bismuth iodide (SBI) induced a considerable increase in light absorption, resultantly leading to the enhancement of solar cell performance by 25%.

Abstract In this study, two Cr atomic layer etching (ALE) methods have been applied for the precise control of Cr etching. The first one involves O radical adsorption followed by Cl + ion desorption (ALE with chemical ion desorption; chemical anisotropic ALE), and the second one involves Cl/O radical adsorption followed by Ar + ion desorption (ALE with physical ion desorption; physical anisotropic ALE). Their effects on Cr etch characteristics were also investigated. For both the ALE methods, sa

Atomic layer etching (ALE) could be an important next-generation etching technique, applicable to various semiconductor materials including III–V compound materials such as indium gallium arsenide (InGaAs) which has high carrier mobility, an advantageous characteristic in nanoscale electronic devices. In this study, the ALE characteristics of InGaAs have been investigated using a reactive ion beam technique. For the ALE of InGaAs, chlorine radicals/low-energy (10–19 eV) reactive ions and low-ene

Rubidium carbonate (Rb2CO3)-doped tris(8-quinolinolato)aluminum (III) (Alq3) thin films have been investigated as electron-injecting materials for organic light-emitting diodes (OLEDs). Electron-only devices consisting of glass/tin-doped indium oxide (ITO)/Rb2CO3-doped Alq3 (10 nm)/aluminum (Al) showed an electron-ohmic contact property between the electrode and the organic layer at the doping concentration of 10% and higher. The electron-injecting ability of these contacts was largely enhanced

Abstract Dry cleaning technology is an essential technique that can be applied to remove native oxide and various contaminants during the semiconductor manufacturing for nanoscale electronic devices. In this study, the in situ dry cleaning of silicon dioxide (SiO 2 ) with low global warming potential (GWP) gas mixtures has been investigated by sequential process steps composed of the reaction of SiO 2 surface by oxygen difluoride (OF 2 ) (GWP: <1)/ammonia (NH 3 ) remote plasma and the removal

A predictor-corrector procedure is presented for the accurate recovery of stresses, displacements and their sensitivity coefficients of multilayered composite panels subjected to mechanical and thermal loads. It is a post-processing procedure combined with the finite element model based on the first order shear deformation theory. The predictor procedure provides only the accurate transverse shear stresses of the panel, in the thickness direction. The corrector procedure following the predictor

A new reliable computational model to predict the hole mobility of poly-crystalline organic semiconductors in thin films was developed. Site energy differences and transfer integrals in crystalline morphologies of organic molecules were obtained from quantum chemical calculations, in which periodic boundary conditions were efficiently applied to capture the interactions with the surrounding molecules in the crystalline organic layer. Then the parameters were employed in kinetic Monte Carlo (kMC)

The blade system of a new concept VTOL vehicle is designed utilizing high performance and Grid computing technologies. The VTOL vehicle called cyclocopter employs a cycloidal propulsion system to generate the propulsion and lift for VTOL maneuver. The structural design and weight minimization of the composite blade system are critically related to the efficiency of whole cyclocopter system. The structural design is carried out using a hybrid genetic algorithm-based optimization framework on the

Recently needs for the convergence of CAD and GIS data are increasing, and many studies on converting two systems to each other are being carried out. In this study, to revise and update the building data of digital map using CAD data for construction, the outline of building is abstracted from the CAD data and the outline is generalized to the same level of detail with the building data of digital map. Several line simplification algorithms to generalize the outline are adopted and compared, es

본 연구에서는 위치기반 소셜 미디어 데이터의 공간적 분포가 지역별 부동산 지수와 어떠한 공간적 관련성을 가지는지에 대해 알아보고자 한다. 두 데이터는 상이한 자료 형식을 가지고 있어, 이를 보완할 수 있는 방법론으로 본 연구에서는 격자 기반의 공간분석 방법을 적용하였다. 대상 데이터로는 2013년 8월 한 달간의 지오태그된 트윗 데이터와 행정구역별 주택가격지수(매매, 전세)를 이용하였으며, 공간적 범위는 서울과 수도권 일부를 포함하도록 하였다. 두 데이터 간의 상이한 공간적 단위를 고려하여 2,000m 단위의 격자망을 구성하고 이에 맞게 두 데이터를 격자 데이터 형태로 변환하였다. 변환된 두 데이터에 대하여 Hot spot 분석을 실시하여 공간적 분포를 시각적으로 비교하였으며, 공간시차를 고려한 이변량 공간적 상관계수를 측정함으로써 정량적 분석을 실시하였다. 시각적, 정량적 분석 결과, 서초구 지역이 트윗 데이터와 주택매매가격지수 데이터에서 공통적인 Hotspot 지역으로 탐색되었으