Arduino와 PLX-DAQ를 이용한 실시간 측정 장치의 물리 실험실에서의 응용

오병성 ( Byungsung O ) 충남대학교 기초과학연구원 2020 충남과학연구지 Vol.37 No.1

The Arduino UNO microcontroller with PLX-DAQ has been tested as a real-time data acquisition system. The Arduino UNO board has analog-digital converters and digital-analog converters with a built-in plotter, which can be programmed with its own Integrated Development Environment. With PLX-DAQ (a data acquisition tool by Parallax) the measured data can be transferred to a spreadsheet and manipulated on PC, Here the capacitor voltage variation during the charging and discharging cycles in the RC circuits was monitored with its own built-in plotter. And the RC time constants were compared with the theoretical values. Finally the Arduino UNO with PLX-DAQ is found to be one of the good tools in undergraduate physics lab.

스마트폰 센서와 마이크로프로세서 기반 측정 장치의 비교

오병성 ( Byungsung O ),박동렬 ( Dongryul Park ) 충남대학교 기초과학연구원 2018 충남과학연구지 Vol.35 No.1

여러 가지 센서가 내장된 스마트폰을 학생 물리 실험에 사용할 수 있기에 가속도 센서와 조도 센서를 추의 주기 측정에 활용하여 보았다. 그 결과를 실험실에서 널리 사용 중인 마이크로 프로세서 장치(MBL)의 결과와 비교하여 보았다. 알맞은 무료 앱을 사용하여 측정 간격을 0.01 s 또는 그 이하로 설정할 수 있어 학생 실험에 활용할 수 있음을 확인하였다. Smartphones with several sensors have been tested for physics lab. In this research, the acceleration and the lux meters were tested for the pendulum motion experiment and compared to the microprocessor-based lab(MBL): a motion sensor and a photogate used in the lab. With the appropriate apps, the measurements can be made every 0.01 s or shorter, which means they could be used instead of MBL equipments in some cases.

ZnSe/CdSe/ZnSe 단일양자우물의 광발광 특성

박재규,오병성,유영문,윤만영,김대중,최용대,Park, J.G.,O, Byung-Sung,Yu, Y.M.,Yoon, M.Y.,Kim, D.J.,Choi, Y.D. 한국진공학회 2007 Applied Science and Convergence Technology Vol.16 No.3

Hot wall epitaxy 방법으로 우물층의 두께를 바꾸어가며 ZnSe/CdSe/ZnSe 단일 양자우물을 성장하였다. 양자우물층의 두께는 TEM을 이용하여 측정하였다. 광발광의 세기와 반치폭의 변화로부터 양자우물층의 임계두께는 약 $9{\AA}$임을 알 수 있었다. 우물층의 두께가 임계두께 보다 작을 때 광발광과 PLE 스펙트럼의 비교로부터 stoke's shift를 확인하였고, 이는 엑시톤 결합 에너지에 의한 것임을 알 수 있었다. 우물층의 두께에 대한 광발광 피크의 에너지 이동은 이론치와 잘 일치하였다. ZnSe/CdSe/ZnSe single quantum wells with different well thickness were grown by hot wall epitaxy. The quantum well thicknesses were measured by TEM. The critical thickness of single quantum well layer was found to be about $9{\AA}$ from the intensities and the full-width at half maximum of photoluminescence(PL) spectra. When the thickness of quantum wells was less than the critical thickness, the Stoke's shift was confirmed from the comparison between PL and photoluminescence excitation spectra, and it may be due to the exciton binding energy. The PL peak energy dependence on the quantum well thickness was coincident with the theoretical values.

LED용 precursor 재이용을 위한 회수 및 정제 공정 개발

양재열,오병성,윤재식,Yang, Jae Yeol,O, Byung Sung,Yoon, Jae Sik 한국자원리싸이클링학회 2014 資源 리싸이클링 Vol.23 No.1

본 연구에서는 metal organic chemical vapor deposition(유기금속화학증기증착, MOCVD) 장치로 부터 LED용 GaN epi 성장 시원료로 사용되는 트리메틸갈륨에 대해서 사용 후 잔량을 회수하고 정제하여 재이용할 수 있는 공정 및 시스템을 개발하고자 한다. 본 공정에서 회수된 트리메틸갈륨에 대해서 화학적, 구조적 특성 평가를 통해서 재이용 가능여부를 검토하였다. 먼저 ICP-MS, ICPAES를 이용하여 순도를 분석한 결과 7N(99.99999%)의 고순도 트리메틸갈륨임을 확인했으며, NMR 분석을 통해서 트리메틸갈륨의 구조적 변화를 확인한 결과, 구조 변화 없이 순수 $(CH_3)_3Ga$(트리메틸갈륨) 구조임을 확인하였다. 또한 회수 트리메틸갈륨에 대한 신뢰성 검토를 위해서 MOCVD 공정을 이용하여 u-GaN를 증착시키고, 결정 특성 평가 및 광학 전기적 특성 평가를 실시하였으며 그 결과, 재이용이 가능함을 알 수 있었다. The purpose of this research is to develop a process and a system to collect, purify and reuse the residual quantity of trimethylgallium, used as a raw material, upon GaN epitaxial growth for LED from a metal organic chemical vapor deposition(MOCVD) equipment. This research reviews whether TMGa collected from the process can be used through a chemical and structural characteristics evaluation. As a result of analyzing the purity using ICP-MS and ICP-AES, 7N high purity (99.99999%) of TMGa was obtained. According to checking the structural change of TMGa through NMR analysis, TMGa having pure $(CH_3)_3Ga$ structure was obtained without structural change. For reliability review of the collected TMGa, u-GaN was deposited using the MOCVD process and an structural, optical and electrical characteristics evaluation was conducted. As a result, it was found out that the reuse was possible.

MOCVD 방법에 의한 Si 기판위 GaN 나노선의 성장

우시관,신대근,오병성,이형규,Woo, Shi-Gwan,Shin, Dae-Keun,O, Byung-Sung,Lee, Hyung-Gyoo 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.11

We have grown GaN nanowires by the low pressure MOCVD method on Ni deposited oxidized Si surface and have established optimum conditions by observing surface microstructure and its photoluminescence. Optimum growth temperature of $880^{\circ}C$, growth time of 30 min, TMG source flow rate of 10 sccm have resulted in dense nanowires on the surface, however further increase of growth time or TMG flow rate has not increased the length of nanowire but has formed nanocrystals. On the contrary, the increase of ammonia flow has increased the length of nanowires and the coverage of nanowire over the surface. The shape of nanowire is needle-like with a Ni droplet at its tip; the length is tens of micron with more than 40 nm in diameter. Low temperature photoluminescence obtained from the sample at optimum growth condition has revealed several peaks related to exciton decay near band-edge, but does not show any characteristic originated from one dimensional quantum confinement. Strong and broad luminescence at 2.2 eV is observed from dense nanowire samples and this suggests that the broad band is related to e-h recombination at the surface state in a nanowire. The current result is implemented to the nanowire device fabrication by nanowire bridging between micro-patterned neighboring Ni catalysis islands.

동시 스퍼터링 방법으로 증착한 ZnO:Al의 전기적 광학적 특성

유동휘 ( Dongwhi Yu ),오병성 ( Byungsung O ) 충남대학교 기초과학연구소 2016 忠南科學硏究誌 Vol.33 No.2

ZnO:Al thin films were grown on sodalime glass by RF magnetron co-sputtering. The RF power for ZnO target was fixed and DC power for Al target was controlled to adjust the Al contents in the films. As the DC power increased, the diffraction angle of XRD peak increased and the FWHM got smaller. The resistivity of the films decreased and the optical energy gap increased with increasing DC power. As the DC power increases, more Al atoms might be substituted with Zn atoms and the free electron density increases. With this increase in free electron density, the resistivity decrease and the optical energy gap increase can be explained. But above the specific DC power, namely above the specific Al contents, Al atoms might become interstitials and the quality of films gets worse (the FWHM of the XRD peak increases and the resistivity decreases).

염기 수용액을 사용한 규소의 비등방성 식각

이정윤 ( Jungyoon Lee ),오병성 ( Byungsung O ) 충남대학교 기초과학연구원 2017 충남과학연구지 Vol.34 No.1

Textured etching with acidic or alkaline solution is widely used to reduce the reflectance of Si wafers for photovoltaic applications. The etching time and solution temperature dependences of the reflectance of mono-crystalline Si wafers were studied with 2% KOH solution. After etching the specular reflectance and total reflectance decreased significantly, especially for the sample etched at 80℃ for 50 min.

PC1D를 이용한 규소 태양전지의 수치 모델

김재석 ( Jae-suk Kim ),오병성 ( Byungsung O ) 충남대학교 기초과학연구소 2016 忠南科學硏究誌 Vol.33 No.1

The main output parameters of a Si solar cell - open-circuit voltage, short-circuit current, and maximum power - have been estimated with one dimensional numerical simulation program, PC-1D. Especially the dependences on p-layer doping density, n-layer doping density and n-layer thickness were investigated and explained. Simple and cheap simulation shows that this kind of programs are so useful to estimate the final results of the designed solar cells prior to the actual expensive fabrication.

VLS 방법으로 성장한 GaN 나노와이어의 특성

양재열 ( Jae Yeol Yang ),오병성 ( Byungsung O ) 충남대학교 기초과학연구원 2019 충남과학연구지 Vol.36 No.1

GaN nanowires have been grown on Ni/GaN epilayer/sapphire substrate by vapor-liquid-solid method with chemical vapor deposition equipment, The substrate temperature was controlled from 600oC to 900oC. The surface morphology was investigated by field-emission scanning electron microscopy. It was found that the nanowires grown around 700oC showed the high quality GaN nanowires with the triangular cross section. X-ray diffraction revealed that the structure of the GaN nanowires have wurzite structure. The temperature-dependent photoluminescence showed the excitonic peaks and the quenching effect was observed.

GaAs/Ge Tandem Solar Cell 에 관한 터널 다이오드 최적화 연구

양수미(S.M.Yang),오병성(B.G.O),이만근(M.G.Lee),차인수(I.S.Cha) 한국태양에너지학회 1998 한국태양에너지학회 논문집 Vol.18 No.1