• 센서학회지
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• 제13권2호
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• pp.128-132
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• 2004

Short wave infrared (SWIR) photovoltaic devices have been fabricated from metal organic vapour phase epitaxy (MOVPE) grown n- on p- HgCdTe films on GaAs substrates. The MOVPE grown films were processed into mesa type discrete devices with wet chemical etching employed for meas delineation and ZnS surface passivatlon. ZnS was thermally evaporated from effusion cell in an ultra high vacuum (UHV) chamber. The main features of the ZnS deposited from effusion cell in UHV chamber are low fixed surface charge density, and small hysteresis. It was found that a negative flat band voltage with -0.6 V has been obtained for Metal Insulator Semiconductor (MIS) capacitor which was evaporated at $910^{\circ}C$ for 90 min. Current-Voltage (I-V) and temperature dependence of the I-V characteristics were measured in the temperature range 80 - 300 K. The Zero bias dynamic resistance-area product ($R_{0}A$) was about $7500{\Omega}-cm^{2}$ at room temperature. The physical mechanisms that dominate dark current properties in the HgCdTe photodiodes are examined by the dependence of the $R_{0}A$ product upon reciprocal temperature. From theoretical considerations and known current expressions for thermal and tunnelling process, the device is shown to be diffusion limited up to 180 K and g-r limited at temperature below this.

• 한국결정성장학회지
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• 제21권3호
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• pp.114-118
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• 2011

본 논문에서는 육각형 GaN 피라미드의 꼭지점 부분에만 나노 혹은 마이크로 크기의 GaN 구조를 선택적으로 성장시킬 수 있는 결정 성장 방볍에 대하여 연구하였다. 최적화된 포토리소그라피 공정을 이용하여 육각형 GaN 피라미드 구조의 꼭지점 부분의 $SiO_2$ 마스크 영역만을 제거할 수 있었으며, 이렇게 하여 노출된 육각형 GaN 피라미드의 꼭지점 부분에만 metal organic vapor phase epitaxy(MOVPE) 결정 성장방법을 사용하여 나노 및 마이크로 크기의 GaN 구조를 선택적으로 성장하였다. GaN 피라미드 꼭지점 부근에 형성된 나노 및 마이크로 G값J 구조는 semi-polar {1-101} 결정면으로 둘러싸인 육각 피라미드 형상을 하고 있으며 그들의 크기는 성장 시간에 의해 쉽게 조절할 수 있음을 확인하였다. TEM 관측 결과, 측면 방향으로 진행하는 관통전위들이 $SiO_2$ 마스크에 의해 효율적으로 차단되어 나노 및 마이크로 GaN 구조에서는 전위 밀도가 감소하는 것을 확인할 수 있었으나 $SiO_2$ 마스크의 끝부분의 매끄럽지 못한 부분에 의해 적층 결함이 발생함을 확인하였다.

• 한국결정성장학회지
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• 제19권1호
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• pp.1-5
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• 2009

본 연구에서는 metal organic vapor phase epitaxy(MOVPF) 방법으로 $8^{\circ}$-off (100) Si 기판 위에 분극이 완화된(1-101) GaN를 성장한 후 광소자로서의 가능성을 확인하고자 (1-101) GaN 위에 InGaN/GaN MQW 구조를 제작하였으며 암모니아 유량, TMI 유랑 그리고 성장 온도 등 다양한 성장 조건에 따른 구조적, 광학적인 특성을 scanning electron microscopy(SEM)와 cathodoluminescence(CL)을 통하여 관찰하였다. (1-101) GaN 성장시 암모니아 유량이 적을수록 관통전위가 현저히 줄어드는 것을 확인하였다. (1-101) GaN stripe 위에 성장 시킨 InGaN/GaN MQW 구조를 이용하여 성장조건에 따라서 391.5nm부터 541.2nm에 이르는 넓은 영역의 범위에서 발광 스펙트럼을 조절할 수 있음을 확인하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.48-49
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• 2005

• 한국재료학회:학술대회논문집
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• 한국재료학회 1993년도 춘계학술발표회
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• pp.72-73
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• 1993

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권2호
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• pp.79-86
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• 2006

N-polar, Ga-polar, and non-polar GaN was grown by MBE and MOVPE using various substrates and influence of polarity has been investigated. The GaN growth by MOVPE is along cplane (0001), c-plane (0001), and a-plane (11-20) direction on c-plane (0001), a-plane (11-20) and r-plane (1-102) sapphire substrate respectively. The polarity of the film has a strong influence on the morphology and the optical properties of PA-MBE grown As-doped GaN layers. Strong blue emission from As-doped GaN was observed only in the case of N-polarity (000-1) layers, which was attributed to the highest concentration of Ga dangling bonds for this polarity of a GaN surface.

• 한국전기전자재료학회논문지
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• 제16권6호
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• pp.471-476
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• 2003

Au/oxide/n-InP Schottky diodes were fabricated from heteroepitaxial InP layers grown on GaAs substrates by the metalorganic vapor phase epitaxy (MOVPE) method from a new combination of source materials: ethyldimethylindium (EDMIn) and tertiarybutylphosphine (TBP). Anodic oxidation technique by using a solution of 10 g of ammonium pentaborate in 100 cc of ethylene glycole as the electrolyte was used to deposit a thin oxide layer. The barrier heights determined from three different techniques, current-voltage (I-V) measurements at room temperature and in the temperature range of 273 K - 373 K, and room temperature capacitance-voltage (C-V) measurements are in good agreement, 0.7 - 0.9 eV which is considerably high as compared to the 0.45 - 0.55 eV in Au/n-InP Schottky diode without a Passivation layer. The ideality factors of 1.1 - 1.3 of the Schottky diodes were also determined from the I-Y characteristics. Deep level transient spectroscopy (DLTS) studies revealed only one shallow electron state at 92.6 meV below the bottom of the conduction band and no deep state in the heteroepitaxial InP layers grown from EDMIn and TBP.

• 한국표면공학회지
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• 제29권5호
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• pp.325-329
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• 1996

We report on p-type arsenic doping of metalorganic vapor phase epitaxially (MOVPE) grown HgCdTe on (100) GaAs. HgCdTe was grown at $370^{\circ}C$ in a horizontal reactor with using dimethy-cadmium, diisoprophyltelluride, and elemental Hg. We used tris-dimethylaminoarsenic (DMAAs) as the metalorganic for p-doping. 4micron thick CdTe and subsequently 10micron thick HgCdTe were grown on (100) GaAs substrate. Interdiffused multilayer process in which thin CdTe and HgTe layers are grown alternately and interdiffused to obtain homogeneous HgCdTe alloys was used. Arsenic was doped during CdTe growth cycle. After growth HgCdTe was annealed at $415^{\circ}C$ for 15 min and then annealed again at $220^{\circ}C$ for 3 hr, both with Hg-saturate condition. We could obtain p-doping from 2.5$\times$$10^{16}$ to 6.6$\times$$10^{17}$$cm^{-3}$, depending on the DMAAs partial pressure. With the dual Hg-annealing, activation of arsenic was aboutt 90%, which was confirmed by SIMS measurement. With only low temperature annealing at $220^{\circ}C$ for 3hr, activation efficiency was about 50%.

• 한국전기전자재료학회논문지
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• 제11권1호
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• pp.12-17
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• 1998

The heteroepitaxial growth of InP and GaInAs on GaAs substrates has been studied by using a new combination of source materials: ethyldimethylindium (EDMIn) and trimethylgallium (TMGa) as group III sources, and tertiarybutylarsine (TBAs) and tertiarybutylphosphine (TBP) as group V sources. Device quality InP heteroepitaxial layers were obtained by using a two-step growth process under atmospheric pressure, involving a growth of an initial nucleation layer at low temperature followed by high temperature annealing and the deposition of epitaxial layer at a growth temperature. The continuity and thickness of nucleation layer were important parameters. The InP layers deposited at 500$^{\circ}$- 55$0^{\circ}C$ are all n-type, and the electron concentration decreases with decreasing TBP/EDMIn molar ratio. The excellent optical quality was revealed by the 4.4 K photoluminescence (PL) measurement with the full width at half maximum (FWHM) of 4.94 meV. Epitaxial Ga\ulcorner\ulcorner\ulcornerIn\ulcorner\ulcorner\ulcornerAs layers have been deposited on GaAs substrates at 500$^{\circ}$ - 55$0^{\circ}C$ by using InP buffer layers. The composition of GaInAs was determined by optical absorption measurements.

• 한국결정성장학회지
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• 제24권4호
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• pp.145-150
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• 2014

3차원적 선택적 결정 성장 방법에 의해 GaN stripe 구조의 꼭지점 부분에만 GaN 나노로드를 성장하였다. GaN stripe의 꼭지점 부분의 $SiO_2$ 만을 최적화된 포토리소그라피 공정을 이용하여 제거하고 이를 선택적 결정 성장을 위한 마스크로 사용하였다. $SiO_2$가 제거된 꼭지점 부근에만 Au 금속을 증착하고, metal organic vapor phase epitaxy(MOVPE) 방법에 의해 GaN stripe의 꼭지점 부분에만 GaN 나노로드의 선택적 성장을 실시하였다. GaN 나노로드의 형상과 크기는 결정 성장 온도와 III족 원료의 공급량에 의해 변화가 있음을 확인하였다. Stripe 꼭지점에 성장된 GaN 나노로드는 단면이 삼각형형태를 가지고 있으며 끝으로 갈수록 점점 폭이 좁아지는 테이퍼 형상을 가지며 성장되었다. TEM 관측 결과, 매우 좁은 영역에서만 선택적 결정 성장이 이루어졌기 때문에 GaN 나노로드에서 관통전위(threading dislocations)는 거의 관찰되지 않음을 확인하였다. 선택성장이 시작되는 부분의 결정면과 GaN 나노로드의 성장방향의 결정면 방향의 차이에 기인하는 적층결함(stacking faults)들이 GaN 나노로드의 중심영역에서 생성되는 것을 관찰할 수 있었다.