Soo-kyung Chang

We have investigated temperature-dependent charge transport behavior in thick reduced graphene oxide (RGO) film. Our results show that charges transport through two parallel percolating conducting pathways. One contains large disordered regions as one of its constituents, so its conductance is determined dominantly by variable range hopping (VRH). The other is composed of small and medium disordered regions and crystalline sp 2 domains, so its conductance is determined by a serial connection of

potential barriers as a function of the gas molecule concentration and devise a fingerprint map of the sensitivity variation corresponding to an individual ratio of two different molecules in a gas mixture. Because the separation of different gas molecule concentrations from gas mixtures is in high demand in the gas-sensing research field, this result will greatly assist in the progress on selective gas sensing.

Various postsynthesis processes for transition metal dichalcogenides have been attempted to control the layer number and defect concentration, on which electrical and optical properties strongly depend. In this work, we monitored changes in the photoluminescence (PL) of molybdenum disulfide (MoS₂) until laser irradiation generated defects on the sample flake and completely etched it away. Higher laser power was required to etch bilayer MoS₂ compared to monolayer MoS<sub>2</

We investigated the homogeneity and tolerance to heat of monolayer MoS₂ using photoluminescence (PL) spectroscopy.

We have observed magnetic-field-induced charged excitonic transitions from one-side-modulation-doped ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ asymmetric double quantum wells (ADQWs) where two low-energy conduction subbands e1 and e2 are coupled strongly, whereas the heavy-hole ground state hh1 is localized mostly in a quantum well. In the presence of a magnetic field applied parallel to the growth axis, the photoluminescence spectrum of the e1-hh1 tra

In this report, existing models for low-frequency excess electrical noise in poly-Si thin-lm transistors are scrutinized and a new model is proposed, in particular, for larg-grain poly-crystalline thin-lm transistors. Major noise sources are considered to be located in the grain boundary region, and the grain boundary is modeled as two independent Schottky diodes connected face-to-face. As the gate bias increases, the grain boundary barrier height decreases and the conduction and therefore the n

The temperature-dependent behavior of p-type transparent semiconducting oxide CuAlO2 singlecrystals prepared by using a flux self-removal method in alumina crucibles was investigated throughtransmittance and photoluminescence (PL) measurements at temperatures from 12 K to roomtemperature. The low-temperature (12 K) PL spectrum shows two weak, broad emission peaks,one at 3.52 eV and the other at 3.08 eV, which we assign to excitonic emission and to defectrelatedemission originating from copper va

We investigated the temperature and the polarization dependence of the near-band-edge photoluminescence (PL) in non-polar (A-plane) ZnO films on R-plane sapphire grown by using plasma-assisted molecular beam epitaxy. We observed the band-edge emissions from the non-polar ZnO film at 3.449 and 3.386 eV, which were identified as a recombination of free excitons and as excitons bound to neutral donors (D0X) respectively. By analyzing the temperature dependent PL spectra, we attributed the transitio

Cu(In,Ga)Se2 (CIGS) solar cells were fabricated by varying the film thickness of the cracker-ZnS (c-ZnS) buffer layer from 0 nm to 20 nm, and performance was found to depend on c-ZnS film thickness. The best cell efficiency of approximately 8% was obtained from the CIGS solar cell with an 8 nm thick-c-ZnS buffer layer. To investigate the primary factor to determine the cell performance, we utilized the impedance spectroscopy (IS) reflecting interface qualities, and capacitance-voltage (CV) profi

본 연구는 구성원들의 창의적인 사고가 중요한 뷰티기업에서 구성원들이 유연하게 다양한 지식을 함양할 수 있는 학습지향성 조직문화에 영향을 미치는 조직문화들을 살펴보고자 하였다. 즉, 본 연구에서는 선행연구를 바탕으로 조직들의 공통적인 조직문화인 집단문화, 개발문화, 위계문화, 합리문화 등을 뷰티기업의 조직문화로 보고, 이 조직문화들이 학습지향성이라는 특수한 조직 문화를 구축하여 구성원들의 직무만족 및 조직몰입 등을 내포한 조직유효성에 영향을 미치는지를 살펴보고자 하였다. 이를 위해 뷰티기업인 ‘J’ 계열사인 ‘J뷰티’, ‘(주)J’, ‘J아카데미’, ‘J헤어살롱’ 등에 종사하는 종업원 600명을 대상으로 연구를 진행하였다. 수집된 표본은 SPSS ver 19.0과 AMOS ver 19.0의 통계프로그램을 이용하여, 신뢰성 및 타당성 검증, 상관관계 분석, 구조방정식 모형분석을 통한 가설을 검증하였다. 분석 결과 뷰티기업의 조직문화 중 집단문화, 개발문화 합리문화는 기업의 학습지향성에

실리콘(Silicon, Si) 기판과 <TEX>$Al_{0.3}Ga_{0.7}As$</TEX>/GaAs 다중 양자 우물(multiple quantum wells, MQWs) 간의 격자 부정합 해소를 위해 <TEX>$AlAs_xSb_{1-x}$</TEX> 층이 단계 성분 변화 완충층(step-graded buffer, SGB)으로 이용되었다. <TEX>$AlAs_xSb_{1-x}$</TEX> 층 상에 형성된 GaAs 층의 RMS 표면 거칠기(root-mean-square surface roughness)는 <TEX>$10{\times}10{\mu}m$</TEX> 원자 힘 현미경(atomic force microscope, AFM) 이미지 상에서 약 1.7 nm로 측정되었다. <TEX>$AlAs_xSb_{1-x}$</TEX>/Si 기판 상에 AlAs/GaAs 단주기 초격자(short period superlattice, SPS)를 이용한 <TEX>$Al_{0.3}Ga_{0.7}As$</