• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.289-290
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• 2006

We report a study of Zn(S)Se/GaAs heterojunction solar cells grown by molecular beam epitaxy (MBE). Zn(S)Se/GaAs heterostructures prepared under different conditions were characterized in-situ by reflection high-energy electron diffraction (RHEED). Structural and electrical properties were investigated with double crystal X-ray diffraction and current-voltage characteristics, respectively. The fabricated $n-ZnS_{0.07}Se_{0.93}/p-GaAs$ solar cell (SC #2) exhibited open circuit voltage($V_{oc}$) of 0.37 V, short circuit current($I_{sc}$) of $1.7{\times}10^{-2}$ mA, fill factor of 0.62 and conversion efficiency of 7.8 % under 38.5 $mW/cm^2$ illumination.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.205-208
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• 2001

Schottky barrier diodes are fabricated on a intrinsic GaN(4${\mu}{\textrm}{m}$) epitaxial structure grown by rf plasma molecular beam epitaxy (MBE) on sapphire substrates. First, We make Ohmic electrodes (Ti/Al/Ti/Au) by evaporator. Next, we contact RuO$_2$ by dipping in the solution (RuCl$_3$.HClO$_4$), and then we deposit Ni/Au on the surface of RuO$_2$ by evaporator. We study the electrical characteristics of GaN Schottky barrier diodes made by these methods. Measurements are C-V, I-V, SEM, EDX, and XRD for the characteristics of devices. Thickness of RuO$_2$ layer depends on supplied voltage and dipping time. Device of thinner RuO$_2$ layer have a good Schottky characteristics compare with device of thicker RuO$_2$ layer

• 전자공학회논문지A
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• 제31A권7호
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• pp.76-84
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• 1994

The characteristics of 3 inch wafer scale GaAs epitaxial wafer grown by molecular beam epitaxy for LSI process application were studied. The thickness and doping uniformity are characterized and discussed. The growth temperature and growth rate were $600^{\circ}C$ by pyrometer, and 1 $\mu$m/h, respectively. It was found that thickness and doping uniformity were 3.97% and 4.74% respectively across the full 3 inch diameter GaAs epitaxial layer. Also, ungated MESFETs have been fabricated and saturation current measurement showed 4.5% uniformity on 3 inch, epitaxial layer, but uniformity of threshold voltage increase up to 9.2% after recess process for MESFET device.

• 전자공학회논문지A
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• 제31A권9호
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• pp.114-120
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• 1994

We have been successfully fabricated the low nois HEMT device with AlGaAs and GaAs structure. The epitazial layer with n-type AlgaAs and undoped GaAs was grown by molecular beam epitaxy(MBE) system. Ohmic resistivity of the ource and drain contact is below 5${\times}10^{6}{\Omega}{\cdot}cm^{2}$ by the rapid thermal annealing (RTA) process. The ideality factor of the Schottky gate is below 1.6 and the gate material was Ti/Pt/Au. The HEMTs with 0.25$\mu$m-long and 200$\mu$m-wide gates have exhibited a noise figure of 0.65dB with associated gain of 9dB at 12GHz, and a transconductance of 208mS/mm.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.288.2-288.2
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• 2014

InP quantum dots were grown by using the molecular beam epitaxy technique. Quantum dots are connected and composed string-like one-dimensional structure due to the strain field along [110] crystal direction. Two prominent photoluminescence transitions from normal quantum dots and string-like one-dimensional structure were observed which show strong optical anisotropy along [1-10] and [110] crystal directions. Both peaks also showed blue-shift while rotating emission polarization from [1-10] to [110] direction. Such optical transition behaviors are the consequence of the valence band mixing caused by strain field along the [110] crystal direction.

• 한국재료학회지
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• 제7권9호
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• pp.805-810
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• 1997

MBE에 의해 성장된 Zn$_{1-x}$ Fe$_{x}$Se박막의 미세구조가 고분해능 투과전자현미경에 의해 연구되었다.Zn$_{1-x}$ Fe$_{x}$Se 박막에서 CuAu-l과 CuPt의 규칙격자가 발견되었다. 이 규칙격자는 전자 회절과 단면 고분해능 격자 이미지에 의해 조사되었다.CuAu-l규칙격자는 (001)InP기판 위에 성장된 Zn$_{1-x}$ Fe$_{x}$Se(x=0.43)에서 관찰되었고, 반면에 CuPt규칙격자는 (001)GaAs기판 위에 성장된 Zn$_{1-x}$ Fe$_{x}$Se(x=0.43)에서 관찰되었다.43)에서 관찰되었다.

• 한국전기전자재료학회논문지
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• 제14권12호
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• pp.972-978
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• 2001

Some effects of Al/N ratio on microstructure of AlN films grown on Si(111) substrates by PAMBE were investigated. Al/N ratio was controlled by rf power of N$_2$ plasma source system. Al excess or N excess conditions were obtained below or above 350 W rf power, respectively. Surface roughness and morphology of AlN film grown at Al/N=1.0 showed the best result. Under Al excess condition, it was suggested that excess Al atoms which did not contribute to the growth of AlN film prevent the normal crystal growth and make abnormal growth of some columns. However, under N excess condition, it was explained that some of the excess active N source turned into gas state and then desorbed out from substrate.

• 한국전기전자재료학회논문지
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• 제13권1호
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• pp.21-27
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• 2000

We used the surface photovoltage spectroscopy(SPVS) for characterization of GaAs/Al\ulcornerGa\ulcornerAs multi-quantum well(MQW) structures grown by molecular beam epitaxy(MBE) method. Energy gap related transitions in GaAs and AlGaAs were observed. The Al composition(x=0.3) was determined by Sek's composition formula. Transition energies in MQW were determined using the differential surface photo-volatage spectroscopy)DSPVS) of the measured resonanced. In order to indentify the transitions, the experimentally observed energies were compared with results of the envelope function approximation for a rectangular quantum well. We have observed and interesting behavior of the temperature dependence(80K~300K) of the 11Hand 11L transition for sample.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.331-332
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• 2005

Ozone is ambient gas which is useful for the fabrication of metal oxide thin films under conditions of molecular beam epitaxy. Ozone is condensed by the adsorption method and its concentration is analyzed using the thermal decomposition method. The concentration of ozone exceeds 90 mol% and ozone is supplied for a sufficiently long time to grow oxide thin films. The ozone concentration is also evaluated using a quadrupole mass analyzer and the accuracy of this method is compared with the results of the thermal decomposition method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.78-79
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• 2005

We report on optically excited terahertz (THz) omission from low-temperature (LT) grown GaAs. We have used 70 fs titanium-sapphire laser pulses with wavelengths at 800 nm to generate THz radiation pulses. The LT-GaAs layers are grown on semi-insulating GaAs substrates with GaAs buffer layer by molecular beam epitaxy (MBE). The THz emission from the LT-GaAs surface is strong and does not show any significant variation in the strength of the THz emission over several different angles between the polarization of the excitation laser pulse and the crystallographic orientation of the LT-GaAs.