化學反應蒸着에 의한 CdS 多結晶 薄膜制作 및 그 特性硏究 (Ⅰ)

강현식,남궁윤,최선우,홍광준,최용대 全北大學校 敎育大學院 1986 敎育論叢 Vol.6 No.-

CdS thin film was fabricated by chemical bath deposition method and polycrystallined by the proper heat treatment. The physical properties of the amorphous and polycrystal of CdS thin film were observed and calculated by measuring the X-ray diffraction patterns, optical absorption, transmission and photoconductivity. From the present experiments, we obtained the energy band gap of the CdS polycrystal thin film to be 2.42eV and the In donor impurity level to be 0.025 eV below the conduction band : Another result was to be a_o=4.13Å and c_o=6.75Å for lattice constants of the hexagonal structure. Also, we attempted it to find the possibility of the application to photosensor. To apply cds this film to the photosensor more sufficiently, further experiments are required to accumulate data on such problems.

CdS:In 單結晶의 基本特性과 photosensor로의 應用

강현식,박병채,장성우,이해익,최용대 全北大學校 敎育大學院 1986 敎育論叢 Vol.6 No.-

The opto-electrical properties of the CdS : In single crystals were studied by these means of the scanning electron microscope, X-ray diffraction, optical transmission & photoconductivity, resitivity variation v.s. impurites, and resitivity v.s. photon flux change. By X-ray diffraction measurement, the structure was found to be hexagonal and the lattice constant was calculated to be a_o=4.13Å and c_o=6.75Å The band gap was estimated to be about 2,419eV (300K). By the transmission measure ments a donor impurity level of In or Al was 0.024eV below the conduction level edge. For the application on the photosensor, the resistivity(ρ) variation of the CdS : In was measured with respect to photon flux(P_o) change and to wavelength, the resistivity was found to be ρ=8.75×10^6P_o^-125 (Ω―㎝/Lux) and the photoconductivity showed its highest response peak between 5,000Å and 5,400Å ranges.

물리교육의 효율적인 교수-학습 지도 방안 : 빛 단원을 중심으로 learning methods of physics education

강현식,박승태,양동익 全北大學校 敎育大學院 1983 敎育論叢 Vol.3 No.-

Teaching physics education, various materials have been used. But many kinds of equipments are not sufficient and their operations are very complecate. On the other hand, it takes a lot of time for preparations. The physical experiments should decide the directions of lectures and motivate the learning students. The most remarkable discovery made by physical science is physical phenomena itself. The central problem in teaching physics today is to establish the principles of physics which consist of the basis of all physical phenomena. And the demonstration experiments are used frequently inside and outside the classrooms, and the operations of experiments are convinient to impulse of interests of students. In order to update the teaching and learning method of physics education effectively, we have studied“LIGHT”in high school's physics using improved method by the experiments though the analysis and investigation of the measuring results.

Cd_xZn_(1-x)Te 단결정을 이용한 초고속 THz 전자파의 emitter 특성연구 (Ⅲ)

강현식,정길환,김태규,이해익 전북대학교 과학교육연구소 2002 과학과 과학교육 논문지 Vol.27 No.-

Cd_xZn_1-xTe single crystal system is most ideal crystal for ultrawere investigated for ultrafast T-ray emitters, with composition ratio x=0.00, 0.05, 0.10, 0.15, 0.20, and 0.25. We have found that Cd_0.05Zn_0.95Te crystals are best emitters for T-ray generation, also for above all composition ratio x=0.05 crystals, T-ray emitting ability depended on resitivity were investigated. The results is that the crystals greater than 100Ω-㎝ are good emitters. We study on the Azumuthal angle dependence of the (110) plane and could be explane the 3fold symmetric variation of signals. Finally we could show the linearity is above the 10^5.

An_~40Cd_~60Te 단결정의 발광소자에 관한 기초연구 (Ⅰ)

강현식 全北大學校 1988 論文集 Vol.30 No.-

Light emitting diodes of the Zn_~(40)Cd_~(60) Te:P-Al were fabricated and their characters were studied. Diodes were made from the phosphor dipped Zn_~(40)Cd_~(60) Te single crystal which were grown by Bridgman method, infiltrating the Aluminum by thermal diffusion method. The characters of single crystals such as energy gap, its variation on the temperature, defect energy levels result on the phosphor dipping and hole concentration were estimated by the measurements of transmission, photoluminescence spectra depending on the temperature and of Hall effects. The diode characters and light emitting characters were studies through the investingating the diffusion layer by stain method, n-layer electron concentration by Hall effects measurements and current-voltage relation, also the emitting light spectra and its intensities depending on currents at 77K.

Zn_39.5Cd_60.5Te 단결정을 이용한 Solar Cell 제작과 그 특성 연구 (Ⅱ) : n형 Zn_39.5Cd_60.5Te 단결정의 열처리에 의한 비저항조절 Resistivity control of the n-type Zn_39.5Cd_60.5Te single crystals by thermal diffusion and heat treatment method

강현식,최용대,김내호 全北大學校 敎育大學院 1985 敎育論叢 Vol.5 No.-

For the control of low resistivity of n-type Zn_39.5 Cd_60.5 Te single crystals, we employed several processes of doping and thermal diffusion using the vapor of Cl_2, I_2, CdI_2, Al and In. As seem to be most proper method we thought, the following techniques were used; 1. In the crystal growing by Bridgman method, I_2 donor impurity (0.025-0.005 atomic wt%) is dopped. 2. The grown crystals are transfered and placed in In-vapor(6 Torr) for 1 hr to diffuse thermally again I_2 into the crystals. 3. And then make to diffuse Cd into the vacancies of Cd among the grown crystals in Cd-vapor (0.25 Torr) for over 5 hrs. As the result, we obtained the n-type Zn_39.5 Cd_60.5 Te crystals having the low resistivity of about 0.1Ω-cm.

CdTe 단결정 반도체의 전기 광학적 특성

강현식 全北大學校 基礎科學硏究所 1981 基礎科學 Vol.4 No.1

Temperature dependence of the band gap and several Interband defect levels of a CdTe; I single crystal which were prepared by Bridgemann method, were evaluated from a series experiment of transmission, photoconductivity, photoluminescence, dark current, and photocurrent variations v.s. light intensity as a function of temperature. The energy band gap were measured 0.61 eV, temperature coefficient β=-4.3×10 exp (-4) eV/^ok by photoconductivity experiments. The interband defect levels, V^-2_cd(0.11eV, β=-1.0×10 exp (-5) eV/^ok), Iodine impurity level(0.012eV at low temperature) and uncertain another level(0.049eV) which were guessed the Oxygen level were observed from above experiments. Also, several, phonon spectrum, LO(0.021 eV), TO_1(0.017eV), and TA_1(0.009eV were observed from photoluminescence experiments in temperature range 38 ^ok∼115^ok.

Ⅱ-Ⅵ족 화합물 반도체 단결정의 전기 광학적인 특성 연구 : ZnTe를 중심으로

강현식 全北大學校 基礎科學硏究所 1979 基礎科學 Vol.2 No.1

Semiconductor crystals of Ⅱ-Ⅳ compounds have more advantages of the large band gap than group Ⅳ or group Ⅲ-Ⅴ compound semiconductors. So, we selected ZnTe, ZnSe and ZnS among the Ⅱ-Ⅵ compounds. It was determined by transmission measurements that the energy gap of ZnTe, ZnSe and ZnS was 2.26eV, 2.67eV, 3.58eV. Especially, ZnTe crystals were grown by the Bridgman method in our Lab. And various heat treatments and impurity dopings were done. We found the impurities levels and Zn vacancy level are 0.11eV for silver, 0.15eV for copper and 0.05ev for V_zn in ZnTe crystals by wave length dependent on photocurrent measurements.

Zn_0.4Cd_0.6Te 단결정의 적외선 발광소자에 관한 기초연구

강현식,장정근,이해익 全北大學校 基礎科學硏究所 1991 基礎科學 Vol.14 No.2

Zn_0.4Cd_0.6Te : Li의 p형 단결정을 Bridgman법으로 성장시키고, 이결정들의 전기적 및 광학적 특성을 조사하였다. 또 이 결정에 Al을 확산시켜 Zn_0.4Cd_0.6Te : Li-Al의 p-n 동성집합 LED을 제작하였고, 이 LED의 특성, 즉 I-V, EL spectrum 및 발광강도의 전류의존성 등을 조사하여 발광천이 관계를 추정하였다. 또 모체결정의 열처리에 따른 발광특성의 변화도 아울러 조사하였고 끝으로 이들의 에너지밴드 모형과 발광천이 관계를 추정하였다. The pure and Li doped Zn_0.4Cd_0.6Te single srystals were grown by Bridgman method respectively, and the their electro-optical properties were investigated by transmission, photoluminescence and Hall effect mesurements. Through carring out the Al vapor-diffusion into the Li doped Zn_0.4Cd_0.6Te crystals in thermal process, the p-n homojunction LEDs, Zn_0.4Cd_0.6Te:Li-Al, were fabricated. The characteristics of LEDs were investigated by measuring the current-voltage, the electroluminescence spectra and emitting light intensity. And also, the characteristics of LEDs prepared with various thermal anealing were compared with each other. Finally, the energy band model were estimated, and the light emitting mechanism was presumed.

Zn_(9.9)Cd_(90.1)Te 단결정 반도체의 전기 광학적 특성

강현식 全北大學校 敎育大學院 1982 敎育論叢 Vol.2 No.-

Zn_9.9Cd_90.1 Te single crystals were grown by Bridgemann method, and lattice constant = 6.438 Åwas determined from X-ray diffraction. Temperature dependence of the band gap and several defect levels of the interband have been found for measurements of transmission, photoconductivity, photoluminescence, and dark current at 30˚K-300˚K. The energy band gap was Eg=1.676eV and temperature coefficient was = -4.8 x 10^-4 eV/˚K. Also, acceptor centers of Vcd^-1, Vcd^-2 and donor centers of I_Te have been found at 0.064_3eV, 0.26eV above the valence band and 0.011_2eV below the conduction band, respectively.