분자선 에피택시법에 의한 GaAs 기판 위의 ZnSSe 성장 및 특성

손정식,배인호,김인수 嶺南大學校 基礎科學硏究所 1997 基礎科學硏究 Vol.17 No.-

The growth and characteristics of ZnSSe on GaAs(001) substrates using Zn, Se, and ZnS sources by molecular beam epitaxy(MBE) have been investigated. The composition of S in ZnSSe epilayer was measured by double crystal X-ray diffraction(DCX) and which was linear functions of flux ratio, P?/P? and growth temperature up to 12%, respectively. Pseudomorphically grown ZnSSe epilayers have mirrorlike surface. The fluctuation of the S composition during ZnSSe epitaxial layer growth was revealed by the DCX rocking curves.

염소가 첨가된 Ⅱ-Ⅵ족 화합물의 광학적, 전기적 특성

손정식,문병연 경운대학교 산업기술연구소 2001 産業技術硏究論文誌 Vol.3 No.2(B)

The optical and electrical properties of Cl-doped ZnSe alloys have been studied by Hall effect and photoluminescence(PL) measurements. By using ZnCl_2 as dopant source, the high quality n-type ZnSe layers with electron concentration up to 1.4×10^19 ㎤ have been achieved. Hall mobility for an epilayer with n = 6.5×10^16 ㎤ are ∼400 ㎠/V.s at 300 K and ∼900㎠/V.s at 80 K. For heavily doped samples, Cl donors are partially compensated. The PL measurements were performed at 11 K and 300 K. The excitonic emission associated with a neutral donor is dominant in the samples doped with Cl concentration below ∼10^19 ㎤. The carrier compensation was discussed with V^Zn-Cl^Se complex as reported origin of self-activated(SA) emission in previous reports.

ZnSe/GaAs 이종접합 구조의 photoreflectance 연구

손정식,문병연 경운대학교 산업기술연구소 2002 産業技術硏究論文誌 Vol.5 No.1(A)

We have studied the interface characteristics of undoped ZnSe/GaAs heterostructure, resulting from the strain between ZnSe and GaAs, using photoreflectance (PR) spectroscopy. For PR spectra measured at room temperature, the two peaks were observed at about 1.4 eV GaAs bandgap region originating from ZnSe/GaAs and GaAs/SI-GaAs interfaces and the shoulder peak was observed at about 2.7 eV ZnSe bandgap region originating from the separation between heavy hole and light hole. we could be determined the origin of two different features observed in the PR spectra by combining in-phase and out-phase measurements of Lock-in amplifier. From PR result, we knew that ZnSe epilayer was partially relaxed due to thick layer thickness over than the critical layer thickness (CLT) and the stress effect caused by these layer relaxation affected the ZnSe/GaAs heterointerface more than the interface of GaAs buffer/SI-GaAs substrate.

ZnSe 박막의 성장온도에 따른 특성연구

손정식,문병연 경운대학교 산업기술연구소 2000 産業技術硏究論文誌 Vol.3 No.1(A)

We have investigated the AnSe thin-film properties with growth temperature. The ZnSe thin-film samples were grown on GaAs substrates by molecular beam epitaxy system. The grown samples were characterized by double crystal X-ray diffractometry and photoluminescence. As increasing growth temperature, the grown ZnSe thin-film thickness was decreased with -1.5 nm/hr℃ by re-evaporation of An and Se molecules on the surface. From the result of photoluminescence measurements, the emission intensity ratio of I₂/X_hh peak was increased, which was explained in terms of the increased density of donor impurity from the Ga inter-diffusion at the interface.

Raman 산란에 의한 InxGa1-xAs/GaAs 이종접합구조의 구조적 특성 연구

손정식,문영희,배인호,김말문 嶺南大學校 基礎科學硏究所 1996 基礎科學硏究 Vol.16 No.-

Using Raman Scattering, we have measured the resiual strain of InGaAs layers with 0≤ x < 0.33 grown on GaAs substrates. The samples under investigation were grown by molecular beam epitaxy system. The In composition was varied from x=0 to x<0.33 and the thickness of epilayer is fixed to 1㎛ which are more thick than critical layer thickness except bulk GaAs(x=0). Our result show that FWHM of GaAs-like LO phonon peak is not significant increase under 80% relaxation but TO/LO ratio is increase with In composition. We calculated relaxation ratio from Raman scattering measurements based on the theory of strain induced phonon shifts and which result compared with DCX measurements.

MPEG-21 표준의 구현을 위한 Testbed 구축

손정화,손현식,조영란,권혁민,김만배 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-

1990년대 후반부터 다양한 디지털 통신망을 이용하여 멀티미디어 컨텐츠 서비스가 가능하게 되었다. 하지만, 멀티미디어 컨텐츠의 전달 및 이용을 위한 기반 구조들의 독자적 발전 및 다양한 통합적 관리 체계 시스템으로 인해, 멀티미디어 컨텐츠 표현 방식의 호환성 문제, 혼재하는 네트워크 전달 방식과 단말 방식의 호환성 문제 등의 잠재적인 문제점이 발생한다. 이런 문제의 대안으로 현재 존재하는 기술 및 기반 구조들 사이의 연동을 통한 큰 프레임워크인 MPEG-21이 진행 중이다. 본 논문에서는 현재 표준화 작업이 진행 중인 MPEG-21을 기반으로 하는 Testbed를 제안한다. Testbed는 server, client, DIA(Digital Item Adaptation)의 세 모듈로 구성된다. Server의 역할은 멀티미디어 컨텐츠를 Digital Item(DI)으로 생성하고, client가 DI를 요구할 경우 DIA 모듈을 통해서 변환된 DI를 client에게 제공한다. DIA 모듈은 server에서 동작되며 client로부터 요청된 DI를 분석하고 client로부터 전송된 환경 정보를 이용하여 client 환경에 적합하게 변환된(adapted) DI를 생성하는 것이 주 기능이다. Client는 server에 저장되어 있는 DI를 선택하고 user preference, terminal capability 등의 필요한 정보를 server로 전송한다. Testbed에서는 스포츠 경기의 동영상, 정지 영상, 경기 내용, 역사를 기록한 파일 등의 DI를 이용한다. 표현 언어는 XML이며, HTTP 기반의 Web 환경에서 구동되도록 설계된다.

Cl이 첨가된 ZnSe의 특성 연구

손정식,김인수,이동건,배인호,박성배 嶺南大學校 基礎科學硏究所 1996 基礎科學硏究 Vol.16 No.-

The electrical and structural properties of Cl-doped ZnSe epilayers have been studied by Hall effect measurement, Photoluminescence(PL), and chemical etching. By using ZnCl₂ as dopant source, the high quality n-type ZnSe layers with electron concentrating up to ?? have been achieved. Hall mobility for an epilayer with ?? are ~ 400 ㎠/V.s at 300 K and ~ 900㎠ /V.s at 80 K. These values are close to those reported for the homoepitaxial layer. For heavily doped samples, Cl donors are partially compensated. The PL measurements were performed at 11 K and 300 K. The excitonic emission associated with a neutral donor is dominant in the samples doped with Cl concentration below ~??. The carrier compensation was discussed with ?? complex as reported origin of self-activated(SA) emission in previous reports. The micrographs of etched surface by Br-methanol dilute solution showed that the lattice defects were increased with doped Cl concentration.

축구포지션별 무산소 운동능력 분석

손장식,정정욱,김종호,임정수,김훈 대구대학교 기초과학연구소 2003 基礎科學硏究 Vol.19 No.3

In this study, the Wingate power test was performed to investigate of the anaerobic power output in soccer players who play in different position. The main purpose of the test was to provide the enhancement of anaerobic capacity which was conducted by comparing and analysing of the Wingate test. This will improve the performance during the soccer games. Seventeen soccer players with three different positions, FW, MF, DF, were recruited, and undertook the Wingate power test, and anaerobic power, peak power output, anaerobic capacity, and fatigue index was analysed. There was a significant effect of a peak power output among positions showing MF>DF>FW (P<.05). MF revealed the highest peak power output at 15 and 30 seconds time points compared to DF and FW. As far as the players' positions were concerned, a relative anaerobic capacity showed a similar results with a peak power output (P<.05; MF>DF>FW). Unlike with these results, the fatigue index in different positions did not show any statistical significant results (P>.05). Based on these results, it was suggested that the systematical training program is required to perform a modern soccer, pressure and total soccer, in MF players. If the physical strength, especially power out, in MF players is enhanced, the results of the soccer games will be also improved.

In_xGal-_xAS/GaAs 시료의 Raman 산란 특성 연구

손정식 경운대학교 산업기술연구소 2001 産業技術硏究論文誌 Vol.3 No.2(C)

Using Raman scattering we have studied the characteristics of in_xGa1-_xAs layers with 0 x < 0.33 grown on GaAs substrates. The samples under investigation were grown by molecular beam epitaxy system. The in composition was varied from x=0 to x< 0.33 and the layer thickness is fixed to 1 which are more thick than critical layer thickness except bulk GaAs(x=0). Our result show that, full width at half maximum(FWHM) of GaAs-like LO phonon peak is not significant increase under 80% relaxation but TO/LO ratio is increase with In composition. We calculated relaxation ratio from Raman scattering measurements based on the theory of strain induced phonon shifts.

연직배수재의 타설심도에 따른 압밀특성

장정욱,박춘식,손대산 국립7개대학공동논문집간행위원회 2005 공업기술연구 Vol.5 No.-

This study analyzed characteristics of soft ground consolidation according to depths of vertical drain. As the result, when the depth ratio of vertical drains (L/D) were 0.5, 0.7, and 1.0, consolidation characteristics were similar up to 70% in consolidation degree under one-dimensional drain condition. However, above this degree, consolidation speed became slower as L/D became smaller. Two-dimensional drain condition also showed a similar tendency, but when L/D was 1.0, the consolidation speed was relatively higher.