동시진공증발법을 이용한 Cu(In,Ga)Se₂ 박막 제작에 관한 연구

박정철,추순남,Park, Jung-Cheul,Chu, Soon-Nam 한국정보통신학회 2012 한국정보통신학회논문지 Vol.16 No.10

동시진공증발법(co-evaporation)으로 Cu(In,Ga)$Se_2$ 박막을 제작하는 논문으로서 1단계($1^{st}$-stage)에서 기판온도(substrate temperature)가 $400^{\circ}C$에서 $In_2Se_3$상($In_2Se_3$ phase)이 존재하였으며 2,3단계($2^{nd}$-stage, $3^{rd}$-stage)에서 기판온도 변화에 따른 흡수 스펙트럼(absorbency spectrum)은 차이가 크지 않다. 이것은 박막의 두께가 전부 $1{\mu}m$ 이상이므로 흡수 스펙트럼(absorbency spectrum)은 거의 차이가 없다. 2,3단계에서 기판온도 변화에 따른 SEM과 XRD를 분석한 결과, 기판온도가 증가할수록 결정구조(crystal structure)의 밀도(density)가 증가하고 기공(vacancy)이 감소하며 $480^{\circ}C$, $500^{\circ}C$에서 Cu(In0.7Ga0.3)$Se_2$상(${\mu}m$)이 형성되었다. This research is based on fabricating Cu(In,Ga)$Se_2$ thin-film by co-evaporation method. On $1^{st}$ - stage, $In_2Se_3$ phase appeared when the substrate temperature reached to $400^{\circ}C$, however, there was small effect between the substrate temperature and absorbency spectrum on $2^{nd}$, $3^{rd}$ - stage because the average thickness of the thin-film was $1{\mu}m$ or higher. SEM and XRD was measured on $2^{nd}$ and $3^{rd}$ stage and it showed as the substrate temperature increases, the density of the crystal structure increased with the decreament of the vacancy. Furthermore, the formation of Cu(In0.7Ga0.3)$Se_2$ phase showed at $480^{\circ}C$ and $500^{\circ}C$.

Si와 GaAs기판 위에 AIN 박막의 전기적 특성

박정철,추순남,권정렬,이헌용,Park, Jung-Cheul,Chu, Soon-Nam,Kwon, Jung-Youl,Lee, Heon-Yong 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.1

To study the effects of $H_2$ gas on AIN insulation thin film, we prepared AIN thin film on Si and GaAs substrate by means of reactive sputtering method using $H_2$ gas as an additives, With treatment conditions of $H_2$ gas AIN thin film shows variable electrical properties such as its crystallization and hysterisis affected to electrical property, As a results, AIN thin film fabricated on Si substrate post-treated with $H_2$ gas for 20 minutes shows much better an insulation property than that of pre-treated, And AIN film treated with $H_2$ gas comparing to non-treated AIN film shows a flat band voltage decreasment. But In GaAs substrate $H_2$ gas does not effect on the flat band voltage.

건물 차양을 위한 RF제어 시스템 제작에 관한 연구

박정철,추순남,Park, Jung-Cheul,Chu, Soon-Nam 한국인터넷방송통신학회 2014 한국인터넷방송통신학회 논문지 Vol.14 No.6

This paper is based on the fabrication of wireless control system for the building shading device. RF Module was controlled by UHF wireless CC1020 chip which has low electrical power and low electrical voltage. Also 447.8625~447.9875 frequency, 4800Baud data rate and 12.5 kHz channel spacing was controlled by the use of SPDT switch and with Microcontroller program. Furthermore, the helical antenna was used. The starting production of 447.8625~447.9875 kHz wireless electrical power was used. As the result, it did not exceed 10dBm which is the standard of low power wireless system. Shading efficiency was measured at 25%, 50%, 75% direction with controlling the interior temperature and the intensity of illumination at the rate of 1 hour. As the result, the intensity of illumination was lowered to 82~87% at 25% direction with $0.6{\sim}1.4^{\circ}C$ lowered temperature. At 50% direction, the intensity of illumination was lowered to 60~68% with $2.3{\sim}4.1^{\circ}C$ lowered temperature. And at 75% direction, the intensity of illumination was lowered to 41~47% with $3.4{\sim}5.1^{\circ}C$ lowered temperature. 본 논문은 건물 차양을 위한 RF 제어 시스템 제작에 관한 연구이다. 저전력, 저전압 UHF 무선 송 수신 칩인 CC1020을 사용하여 주파수 447.8625~447.9875, Data rate 4800Baud, Channel spacing 12.5kHz, SPDT 스위치로 입출력 분리하여 설계하여 Microcontroller 프로그램 하였다. 안테나는 나선형 Helical 안테나 형태로 제작하였다. 시작 제품을 주파수 447.8625~447.9875 무선 공중선 전력을 측정하여 실험한 결과 소출력 무선기기 기준인 10dBm을 넘지 않았다. 차양 효과 실험은 차양을 25%, 50%, 75% 위치에서 실내 온도 및 조도를 1시간 단위로 측정하였다. 실험결과 25% 위치시 조도는 82~87%로 낮아지고, 온도는 $0.6{\sim}1.4^{\circ}C$ 낮아졌으며, 50% 위치시 조도는 60~68%로 낮아지고, 온도는 $2.3{\sim}4.1^{\circ}C$ 낮아졌다. 75% 위치시 조도는 41~47% 낮아지고, 온도는 $3.4{\sim}5.1^{\circ}C$가 낮아졌다.

기판 온도 변화에 따른 Cu(In,Ga)Se₂ 박막에 관한 연구

박정철,추순남,Park, Jung-Cheul,Chu, Soon-Nam 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.12

In this paper, we prepared $Cu(In,Ga)Se_2$ thin films by using co-evaporation method, and analyzed the properties of the thin films. During the thin film preparation process, we confirmed $InGaSe_2$ phase was formed at $400^{\circ}C$ in first stage, and also confirmed the thin films showed the vacancy decrease. In second and third stage, we confirmed the density increase of crystalline structure at over $480^{\circ}C$ and the formation of $Cu(In_{0.7}Ga_{0.3})Se_2$ phase. As the result of SEM and XRD analysis of the films which were before and after heat-treated, we confirmed the disappearance of $Cu_2Se_2$ and the formation of $Cu(In_{0.7}Ga_{0.3})Se_2$ single phase after the heat-treatment, We, therefore, confirmed the heat-treatment did not affect the absorbency spectra of the thin films.

CuInSe₂ 박막의 열처리에 의한 특성분석

박정철,추순남,Park, Jung-Cheul,Chu, Soon-Nam 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.2

In this paper, $CuInSe_2$ thin film was prepared by use of the co-evaporation method with the variation of the substrate temperature in the range of $100^{\circ}C$ to $400^{\circ}C$. The film was annealed at $300^{\circ}C$ for an hour in a vacuum chamber at $3{\times}10-4$ Pa. After annealing, the thin film prepared at the substrate temperatures of $100^{\circ}C$ and $200^{\circ}C$ was observed. The XRD (x-ray diffraction) pattern of sample prepared at $100^{\circ}C$ showed the single phase formation of $CuInSe_2$. However, at $200^{\circ}C$, there was no apparent difference in the XRD pattern except a variation in the intensity of the peak. As the annealing treatment of substrate improved the crystal structure of the film, it affected to the increase of an electron mobility, resulted in an increase in conductivity and a decrease in resistance. As a results, when the substrate temperature was at $200^{\circ}C$ and $300^{\circ}C$, the sheet resistance was 1.534 $\Omega/\Box$ and 1.554 $\Omega/\Box$, respectively, and the resistivity was $1.76{\times}10-6\;{\Omega}{\cdot}cm$ and $1.7210-6\;{\Omega}{\cdot}cm$, respectively. From the absorption spectrum measurements, there was no variation between the before and after annealing conductions. And it means that the annealing step does not affect the thickness of the thin film.

태양전지용 CdS 박막의 열처리에 따른 전기 및 광학적 특성에 관한 연구

박정철,추순남,Park, Jung-Cheul,Chu, Soon-Nam 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.11

In this paper, CdS thin films well-known to window layer for solar cell were fabricated by means of vacuum evaporation method treated with different substrate heating. During film fabrication the substrates were heated at 50, 75 and $100^{\circ}C$, respectively. The thin films were then annealed at $200^{\circ}C$ in atmosphere, and the electrical and optical properties were investigated. By annealing, the hexagonal structure of films was changed into cubic structure. Their transmissivity was also increased and moved to longer wave band. It was shown that the film fabricated with the substrate heat-treated at $50^{\circ}C$ had the lowest resistivity.

체질처방 및 오행침 치료로 호전된 혈청 음성 류마티스 관절염 환자의 증례보고 3례

박정철,송윤경,임형호,Park, Jung-Chul,Song, Yun-Kyung,Lim, Hyung-Ho 척추신경추나의학회 2010 척추신경추나의학회지 Vol.5 No.1

본 증례의 환자들은 수지관절 및 완관절 등에 통증을 주소로 하는 환자들로 침치료 및 한약물 치료로 유의한 호전을 보였기에 이를 보고하는 바이다. Objectives: This study is to report three cases those have an meaning for rheumatoid arthritis treatment by oriental medicine. In this case rheumatoid arthritis patients have phalangeal and carpal joints disorder mainly. Methods: These patients were treated by acupuncture and herb medication. Results: After treatment, the conditions of patients were improved with oriental medicine, so in two cases rheumatoid arthritis disappeared, but in one case rheumatoid arthritis not appeared. Conclusions: These results suggested that oriental medical treatment was effective to improve the condition of rheumatoid arthritis patients.

Bisphosphonates induced osteonecrosis of the jaw의 기전, 예방, 위험 평가 및 치료 방법

박정철,정의원,김창성,조규성,채중규,김종관,최성호,Park, Jung-Chul,Jung, Ui-Won,Kim, Chang-Sung,Cho, Kyoo-Sung,Chai, Jung-Kiu,Kim, Chong-Kwan,Choi, Seong-Ho 대한치주과학회 2009 Journal of Periodontal & Implant Science Vol.39 No.1

Purpose: Bisphosphonates are drugs used to suppress osteoclastic activity and to treat osteoporosis, Paget's disease of bone and bone metastasis. The purpose of this report is to review the literatures on bisphosphonates use that could affect bone healing and cause osteonecrosis of the jaws. Materials and methods: Medline research was carried out to find relevant articles on bisphosphonates and osteonecrosis of the jaw. Results: Oral administration of bisphosphonates is reported to decrease the risk of adverse bone outcomes. On the contrary, IV bisphosphonates is known to significantly increase the risk. Prevention of the osteonecrosis of the jaw is primary concern before usage. If the adverse bone reaction takes place, proper management and treatments are required to alleviate pain of patients and prevent further progression of necrosis. Conclusion: Case reports of bisphosphonates induced osteonecrosis of the jaw are increasing. Dentists and physicians should be aware of the higher frequency of osteonecrosis of the jaw in patients receiving IV bisphosphonates and be prepared to prevent and cope with adverse bone reaction.

Infrared Spectroscopic Evidences for the Superconductivity of $La_2CuO_4$-related Compounds: A Superconductivity Probe

박정철,조선욱,정종학,정기호,Park, Jeong Cheol,Jo, Seon Woog,Jeong, Jong Hak,Jeong, Gi Ho Korean Chemical Society 2000 Bulletin of the Korean Chemical Society Vol.21 No.10

We present the effects of temperature (between 10 K and 298 K) and of hole concentration on the frequency and intensity of characteristic phonons in polycrystalline $La_2CuO_4-related$ compounds using FT-IR spectros-copy. The influences of the concentration of carrier doped on the phonon modes are prominent in the IR spectra of $La_2CuO_4-related$ compounds. For $La_2-xSrxCuO_4({\chi}=$ 0.00, 0.03, 0.07, 0.10, and 0.15) and electrochemically (or chemically) oxidized $La_2CuO_4$, the intensities of the transverse oxygen mode around 680cm $-^1$ which cor-responds mainly to Cu-O(1) stretching vibration in the basal plane of CuO6 octahedron, are decreased and dis-appeared depending on the Sr-substitution rate and the amount of excess oxygen, while the longitudinal oxygen mode around 510 cm $-^1$ corresponding to the Cu-O(2) stretching in the basal plane of CuO6 octahedron are near-ly invariable. In particular, after two cycles of cooling-heating between 10 K and 298 K for these sample, the phonons around 680 cm $-^1$ are blue shif 13-15 cm $-^1$, while the phonons around 510 cm $-^1$ are nearly constant. The introduction of the charge carrier by doping would give rise to the small contraction of CuO6 oc-tahedron as Cu $^3+$ requires a smaller site than Cu $^2+$, which results in the shortening of the Cu-O(1) bond length and Cu-O(2) bond length with the increased La-O(2) bond length. These results in the frequency shift of the characteristic phonons. The IR spectra of $La_2Li0.5Cu0.5O_4$ which exhibits an insulator behavior despite the $Cu^3+$ of nearly 100%, corroborate our IR interpretations. The mode around 710 cm $-^1$ corresponding to Cu-O(1) stretching vibration is still strongly remained even at low temperature (10 K). Thus, we conclude that the con-duction electrons formed within $CuO_2$ planes of $La_2CuO_4-related$ superconductors screen more effectively the transverse oxygen breathing mode around 680 $cm-^1$ depending on the concentration of the doped charge carrier in $La_2CuO_4-related$ compounds, which might use as a superconductivity probe.

CdS 박막의 기판온도 변화에 따른 전기 및 광학적 특성

박정철,이우식,추순남,조용준,전용우,Park, Jung-Cheul,Lee, Woo-Sik,Chu, Soon-Nam,Cho, Yong-Joon,Jeon, Yong-Woo 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.9

In this paper, CdS thin films for the use of window layer in solar cell were fabricated by vacuum evaporation method to improve the reproducibility, The electrical and optical properties of thin films with the variations of substrates temperature and the variations of the film thickness were investigated. As increasing the substrates temperature the resistivities of films were increased. The samples transmissivity were shown over 70% when the wavelength were above 500 nm. In the films with 280 nm thickness, its transmissivity were reached 100%. The resistivities of the samples were decreased as increasing its thickness.