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HgCdTe를 이용한 Infrared Detector의 제조와 특성
김재묵,서상희,이희철,한석룡 한국군사과학기술학회 1998 한국군사과학기술학회지 Vol.1 No.1
HgCdTe Is the most versatile material for the developing infrared devices. Not like III-V compound semiconductors or silicon-based photo-detecting materials, HgCdTe has unique characteristics such as adjustable bandgap, very high electron mobility, and large difference between electron and hole mobilities. Many research groups have been interested in this material since early 70's, but mainly due to its thermodynamic difficulties for preparing materials, no single growth technique is appreciated as a standard growth technique in this research field. Solid state recrystallization(SSR), travelling heater method(THM), and Bridgman growth are major techniques used to grow bulk HgCdTe material. Materials with high quality and purity can be grown using these bulk growth techniques, however, due to the large separation between solidus and liquidus line on the phase diagram, it is very difficult to grow large materials with minimun defects. Various epitaxial growth techniques were adopted to get large area HgCdTe and among them liquid phase epitaxy(LPE), metal organic chemical vapor deposition(MOCVD), and molecular beam epitaxy(MBE) are most frequently used techniques. There are also various types of photo-detectors utilizing HgCdTe materials, and photovoltaic and photoconductive devices are most interested types of detectors up to these days. For the larger may detectors, photovoltaic devices have some advantages over power-requiring photoconductive devices. In this paper we reported the main results on the HgCdTe growing and characterization including LPE and MOCVD, device fabrication and its characteristics such as single element and linear array($8{\times}1$ PC, $128{\times}1$ PV and 4120{\times}1$ PC). Also we included the results of the dewar manufacturing, assembling, and optical and environmental test of the detectors.
마그네슘 擴散處理에 依한 鑄鐵의 黑鉛 形態變化에 關한 硏究
金在默 연세대학교 대학원 1973 원우론집 Vol.1 No.1
The effects of magnesium diffusion on the spheroidization of flake graphite with Fe-C and Fe-C-Si alloys have been investigated by means of microscopy. In this study, solid cast iron was immerged in molten magnesium bath to diffuse magnesium into the cast iron. The spheroidization of the flake graphite was accomplished by the magnesium diffusion. The results obtained from this experimental work are summarized as follows: 1) The flake graphite near the surface of the cast iron was changed to the fine nodular or lump shape by the magnesium diffusion. 2) The thickness of diffusion layer formed by the magnesium diffusion, which is dependent on the diffusion temperature, time and carbon equivalent, was about 0.2mm to 0.4mm. 3) Graphite content was decreased in the surface layer where magnesium diffused graphite was accumulated under the diffusion layer. 4) In the Fe-C-Si alloy, the shape of graphite formed on the surface became more spherical with the increase in silicon content. 5) With the X-ray diffraction patterns, it was considered that certain intermetallic compound was formed in the diffusion layer.
김재묵,한철희,Kim, Jaemuk,Han, Cheolhuei 한국교통대학교 융복합기술연구소 2021 융ㆍ복합기술연구소 논문집 Vol.11 No.1
편대비행 항공기들은 선행항공기에서 발생시킨 후류의 영향으로 후행항공기의 공력효율이 증가하는 것으로 잘 알려져 있다. 비점성 비회전 유동장에 관한 연속방정식을 지배방정식으로 사용하는 패널법은 비교적 빠른 시간 이내에 항공기의 공력특성 변화를 계산할 수 있는 장점이 있다. 본 연구에서는 편대비행 항공기들 사이의 항공기들 사이의 흐름방향 거리는 스팬길이의 2.5배로 위치시키고, 수평상대거리는 스팬길이의 -0.4~0.3배로, 수직상대거리는 스팬길이의 -0.25, -0.15.0.15.0.25배로 변화시키며 계산을 수행했다. 연구결과 선행항공기와 후행항공기의 수평상대거리 변화의 경우 주날개들이 안쪽으로 겹침이 발생하고, 수직 상대거리가 가까울수록 더 큰 공력성능 향상을 얻을 수 있었다. 편대비행 하는 후행항공기의 공력성능 향상은 선행 항공기로부터 발생한 익단 와류의 올려흐름 영향에 기인한 것이다. 선행항공기로부터 발생한 익단와류는 후행항공기의 모멘트 특성을 변화시켜 비행안정성에 영향을 미치게 된다. 향후 연구에서는 선행항공기로부터 발생한 와의 영향이 후행항공기의 모멘트 특성에 미치는 영향을 연구 할 것이다.
Hg-annealing 온도가 LPE 법으로 성장시킨 Hg0.8Cd0.2Te 의 전기적 특성에 미치는 영향
김재묵,서상희,문성욱,최종술,정용택 대한금속재료학회(대한금속학회) 1990 대한금속·재료학회지 Vol.28 No.6
Hg_(0.8)Cd_(0.2)Te epitaxial layers were grown by an LPE(liquid phase epitaxy) process. As-grown Hg_(0.8)Cd_(0.2)Te showed p-type conductivity with a carrier concentration of 8.8×10^(17)㎝^(-3). Annealings of as-grown Hg_(0.8)Cd_(0.2)Te wafers in Hg-atmosphere were performed over the temperature range 200 to 430℃. Annealings below 300℃ resulted in n-type conductivity with carrier concentrations from 10^14 to 10^15 cm^-3 and showed a maximum value at about 260℃. p→in type conversion temperature is thought to be determined by Hg-interstitials rather than residual donor impurities. The phase boundary of Hg_(0.8)Cd_(0.2)Te on the metal-rich side could be obtained.
(111) CdTe 기판의 이탈방위각이 LPE 법으로 성장시킨 Hg0.7Cd0.3Te 박막의 표면 형상에 미치는 영향
김재묵,서상희,임성욱,최인훈,곽로정 대한금속재료학회(대한금속학회) 1991 대한금속·재료학회지 Vol.29 No.1
Hg_(0.7)Cd_(0.3)Te epilayers were grown by a silder-type LPE(liquid phase epitaxy) technique using Te-rich growth solution. CdTe substrates of (111)Cd orientation with various degrees of misorientation were prepared by vertical Bridgman crystal growth and subsequent chemo-mechanical polishing processes. Epi-layers, which were grown using a substrate with 1^0 misoriented toward four different directions, showed a typical terrace morphology with terrace fronts perpendicular to the misorientation directions. As the misoriented angle increases, the terrace width decreases, while the terrace height increases. With the misorientation larger than 2^0, the terrace structure begins to disappear transforming into a wave-like surface. The initial stage of the epi-layer growth is thought to be governed by the so-called step bunching process. Dislocations begin to play a major role in the growth process when the terrace becomes as wide as 10 to 30㎛. Epi-layers were examined by Nomarski differential interference contrast optical microscope and stylus
Hgo07Cd0.3Te 박막의 LPE 성장시 성장시간에 따른 표면형상의 변화
김재묵,송원준,서상희,임성욱,최인훈,문성욱 대한금속재료학회(대한금속학회) 1990 대한금속·재료학회지 Vol.28 No.2
HgCdTe is the most widely used material for infrared photodetectors. HgCdTe epi-layers were grown on CdTe substrates with (111) orientation, using a slider LPE(Liquid Phase Epitaxy) technique. The change of surface morphology during LPE growth of Hg_(0.7)Cd_(0.3)Te was investigated. The wave-like surface at the initial stage of growth has transformed gradually to the terrace-like surface and the terrace width has increased with increasing growth time. Infrared tansmission was used to determine the composition of HgCdTe epi-layers.
수직 Bridgman 법에 의한 CdTe 단결정 성장시 성장속도가 전위 밀도와 분포에 미치는 영향
김재묵,송원준,서상희,임성욱,최인훈 대한금속재료학회(대한금속학회) 1988 대한금속·재료학회지 Vol.26 No.8
CdTe single crystals were grown by a vertical Bridgman method. The growth rate was varied between 1.1 and 5.4 ㎜/hr with maintaining the temperature gradient of 16℃/㎝ at the solid-liquid interface. Etch-pit structures of CdTe single crystals were investigated. The dislocation density was larger and the subgrain size was smaller at the surface and bottom of the crystal. With the increasing growth rate, the dislocation density gets larger and the subgrain size becomes smaller The thermal stress, which is supposed to build up during the solidification process, can explain our results.