극소전계전자방출 전류밀도 검출을 위한 센싱 시스템 개발

류정탁,K., Oura,김연보 대구대학교 정보통신연구소 2003 情報通信硏究 Vol.1 No.2

본 연구에서 개발된 전계전자방출 측정 시스템은 FE(field emission) 디바이스 전체에 대한 전기적 특성을 평가할 수 있을 뿐만 아니라 극미소한 영역에 대한 전계적 특성도 측정할 수 있다. 따라서 FE 디바이스의 물리적 및 전기적 특성을 보다 정밀하게 마이크로 단위로 평가할 수 있어 우수한 FE 디바이스의 개발 및 개선에 큰 도움을 줄 수 있다. 또한 이 극소전계전자방출 측정 시스템은 FE 디바이스가 전계에 의해 방출하는 전류밀도를 2차원적 및 3차원적으로 표시가 가능하므로 FE 디바이스의 특성을 직관적으로 평가할 수 있다. In this research, we developed the electric field electron emission measurement system of new form. This system can measure electric field characteristic about a microscopic area as well as all over area of a field emission (FE) device. Therefore, this system can give big help in development and improvement of more superior FE device because of measurement capacity for physical and electric property of FE device about a microscopic area. Also, we can intuitionally evaluate FE device characterization, because this system displays possible two-dimensional and three-dimensional current density emitted from FE device by electric field.

무선 기반의 실내 온도 측정 시스템 설계

차부상,정우철,류정탁,김연보 대구대학교 정보통신연구소 2004 情報通信硏究 Vol.3 No.2

최근 홈 네트워크 산업이나 지능형 주거관리 시스템의 필요성과 관심이 증가하고 있다. 이와 같은 분야에서는 무엇보다 효율적인 측정 시스템에 대한 연구가 선행되어야 한다. 따라서 본 논문에서는 센서 측정 시스템 설계에 관한 기초 연구로서 실내 환경에 적합한 온도 측정 시스템을 설계해 보고 그 특성에 대해 나타내었다. 설계한 시스템의 구성은 크게 온도 센서로부터 온도 변화를 검출하는 데이터 획득부, 신호처리를 위한 제어부 그리고 측정된 온도 데이터를 전송하기 위한 RF 송수신부로 나누어진다. 설계된 측정 시스템에 거리변화 및 장애물 유무에 따른 영향을 살펴보고, 안테나 변경에 따른 성능 차이를 살펴보았다. 실험 결과 10m 이내의 실내 환경에서는 본 논문에서 제안하고 설계한 측정 시스템을 사용하여 데이터의 실시간 처리가 가능하였다. 또한 이를 바탕으로 다중 센서 측정 시스템 구현이 가능함을 알 수 있었다. Recently, the need for intelligent sweet home systems and home network industry is increasing. In this field, a study on efficient measurement system is preceded by the other subjects. Therefore, in this paper, a study on efficient sensor measurement system, temperature measurement system suitable for room environment is designed and its property is given. We designed temperature measurement systems consisting of data acquisition part as a temperature sensor, control unit for signal processing and RF moduls for data transmit. The results of experiment showed real-time processing in the room environment within 10 meter. It also showed the possibility of multi-sensors measurement system.

2-2형 압전복합체의 전기적 특성

김연보,류정탁 대구대학교 정보통신연구소 2003 情報通信硏究 Vol.1 No.2

In this study, we have investigated on the development of ultrasonic transducers with 2-2 mode piezocomposites that have better piezoelectric activity and lower acoustic impedance than those of conventional piezoceramics. The piezocomposite ultrasonic transducer can solve the traditional acoustic impedance mismatching problems without the help of matching layers. In this study we have designed optimal material properties of the piezocomposite, and volume fraction and geometric shape of the piezoceramic. The accoustic impedance of 2-2 mode piezocomposite was linearly decreased with PZT volume fraction. The electromechanical coupling factor(kt) was uniformed about 0.68 in the 0.2 to 0.6. When the volume fraction of PZT was 0.2 the accoustic impedance was 3.2 Mrayl.

LPCD법에 의한 Tin박막의 전계 에미터 어레이 제작

조경제,이상윤,류정탁,김연보,이진호 大邱大學校 科學技術硏究所 2001 科學技術硏究 Vol.8 No.2

Using low pressure chemical vapor deposition (LPCVD), TiN thin films as field emitter array were fabricated. In this Work, a method was transfered to a substrate and the wet-etching of the silicon substrate instead of fabricated method of mold shape was using in generally but we have fabricated gated field emitter tips as using mold shape of the new method that using a side wall space structure. Following sequences such as LPCVD method of a gate electrod and gate oxide on a silicon substrate and defesited BPSG thin film as a high temperature was flowed by the mold shape of a sharpen, the TiN as a materials of emitter tips was deposited after was bounded by anodic bonding and the wet-etching of the silicon substrate by using KOII solution, the last have fabricated a gated field emitter arrays of a sharpen. These emitters were estmated by scanning electron microscopy and X-ray diffraction.

Field electron emission from amorphous carbon thin films grown by RF magnetron sputtering

Jeong-Tak Ryu,Shin-Ichi Honda,Mitsuhiro Katayama,Kenjiro Oura 한국물리학회 2005 Current Applied Physics Vol.5 No.4

Using a RF magnetron sputtering, amorphous carbon (a-C) and N-doped a-C (a-C:N) thin lms were fabricated as eld electronemitter. These thin lms were deposited on Si(001) substrate at several temperatures. The eld emission property was improved fora-C thin lms grown at higher substrate temperatures. Furthermore, a-C:N lm exhibits eld emission property better than that ofundoped a-C lm. These results are explained in terms of the change in surface morphology and structural properties of a-C lm..

질소 플라즈마처리에 의한 a-C 박막의 전계방출특성 변화에 관한 연구

Ryu, Jeong-Tak,Lee, K.Y.,Honda, S.,Katayama M.,Oura, K. 한국전기전자재료학회 2004 전기전자재료학회논문지 Vol.17 No.12

Amorphous carbon (a-C) films have been deposited on Si(100) substrate using RF magnetron system in order to investigate the electron field emission properties. The a-C films were treated by $N_2$ gas plasma at room temperature. Surface morphologices and structural properties of the a-C films before and after $N_2$ plasma treatment were observed by scanning electron microscopy and Raman spectroscope, respectively. Structural properties and surface morphology of the a-C films were changed by $N_2$ plasma treatment. The emission properties can be improved by the plasma treatment according to the contents of nitrogen on the a-C films which is varied by plasma treatment time. Before the plasma treatment, the a-C films are found to have a threshold field of 14 V/$\mu$m, but the a-C film treated by $N_2$ plasma for 30 min exhibit threshold field as low as 6.5 V/$\mu$m.

나노입자가 내장된 기능성 박막의 제작과 전자소자 특성

Ryu, Jeong-Tak,Ikuno, T,Honda, S.,Katayama, M.,Oura, K. 한국산업정보학회 2006 한국산업정보학회논문지 Vol.11 No.4

본 논문에서는 DC 플라즈마와 금속유기물을 사용하여 CNF의 저온 합성에 성공하였다. 합성된 CNTs는 기판의 위치에 따라 매우 다른 특성 차이가 보였다. CNT는 일반적으로 직경 100 nm, 길이 $10{\mu}m$의 특성을 가진다. CNT의 형태적 특성들은 전계전자방출특성에 큰 영향을 준다는 사실을 본 연구를 통해 알 수 있었다. 따라서 CNF의 합성에 의한 CNF 구조적 특성은 전자소자응용면에서 매우 중요한 역할을 한다. Carbon nanofibers have synthesized a low temperature using DC Ar plasma and Fe-Phthalocyanine, and a characteristic difference of the synthesized CNF according to the location of the substrate was investigated. The carbon nanofibers had about 100nm diameter and up to $10{\mu}m$ length. These were grown in random orientation. There are two shapes in the CNFs, screw and straight line shapes. Furthermore, we found the selective growth of nanofibers on the scratched substrates. The density of CNFs synthesized on the position (a) were higher than that synthesized on the position (b) [See the Fig. 2]. Also, the length of CNFs was different. In the shape, CNFs with screw and straight line shape were synthesized in the position (a), but. only CNFs with straight line shape were synthesized in the position (b). The difference have an important effect on the field emission characteristics.

ADSORPTION OF ATOMIC-HYDROGAN ON THE Si(100)-(2×1)-SB SURFACE STUDIED BY TOF-ICISS/LEED

Jeong-Tak Ryu,Koichiro Kui,Mitsuhiro Katayama,Kenjiro Oura 한국표면공학회 1996 한국표면공학회지 Vol.29 No.6

High Efficiency InGaN Blue Light-Emitting Diode With <tex> ${>}{\rm 4}\hbox{-}{\rm W}$</tex> Output Power at 3 A

Tak Jeong,Hyung-Jo Park,Jin-Woo Ju,Hwa Sub Oh,Jong-Hyeob Baek,Jun-Seok Ha,Guen-Hwan Ryu,Han-Youl Ryu IEEE 2014 IEEE photonics technology letters Vol.26 No.7

<P>This letter reports high-power and high-efficiency characteristics of the InGaN-based blue light-emitting diode (LED) operating at > 10-W electrical input power in a single-chip package. The LED chip is fabricated as a vertical-injection structure with chip dimensions of 1.8 mm × 1.8 mm. InGaN/GaN short-period superlattice (SL) structures are employed below multiple-quantum-well active region as current spreading layers. It is found, by simulation, that SL layers are quite effective in improving current spreading and uniformity in carrier distribution. When the characteristics of the fabricated LED package are measured under pulsed operation conditions, efficiency droop is found to be greatly reduced in the LED structure with SL layers. A record high light output power of 4.18 W and external quantum efficiency of 51% are demonstrated at 3-A injection current.</P>

용접 와이어 직경이 용접 상태 검출에 미치는 영향

류정탁(Jeong Tak Ryu) 한국산업정보학회 2016 한국산업정보학회논문지 Vol.21 No.2

본 연구에서는 용접전류 및 용접전압 신호처리에 의한 용접 상태 검출에 있어 용접 와이어의 직경이 미치는 영향에 관하여 연구하였다. 실험을 위하여 인위적으로 모재의 간격을 용접 와이어보다 작은 경우와 큰 경우에 대하여 분석하였다. 사용된 용접 와이어의 직경은 1.2 mm이었으며 인위적으로 형성한 용접 모재 사이의 간격은 1.0 mm와 2.0 mm 두 종류를 사용하였다. 실험결과 용접 와이어의 직경보다 큰 용접 결함 요인에 대하여서는 용접전류 및 용접전압의 변화를 감지할 수 있으나 직경보다 작은 용접 결함 요인에 대하여서는 용접전류 및 용접전압의 변화를 감지할 수 없었다. Using the welding current and voltage signal processing, we have studied the influence that the diameter of the welding wire to the welding quality detection. For the experiments, We have analyzed the signal with respect to large and small artificially a gap between base materials than the welding wire. In this experiment, the 1.2 mm diameter of the welding wire was used, and distance between the welding base materials was respectively 1.0 mm and 2.0 mm. In the welding with a large defect than the diameter of the welding wire it was able to detect a change in the welding current and welding voltage. But it could not detect a change in the welding current and welding voltage in the welding has a small defect than the welding wire diameter.