• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.175-175
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• 2009

AZO, GZO, ZIO 박막은 DC 마그네트론 법으로 각각의 소결체 타겟을 사용하여 유리 기판위에 증착되었다. 상온에서 증착된 GZO 박막의 경우 $1.61{\times}10^{-3}{\Omega}cm$ 의 가장 낮은 비저항을 나타내었다. 전기적 특성을 향상시키기 위하여 기판온도를 상승하였을 때 역시 GZO 박막이 가장 낮은 $6.413{\times}10^{-4}{\Omega}cm$ 을 나타내었다.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.49-54
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• 2020

We studied the electronic and magnetic properties for the Mn-doped chalcopyrite (CH) AlAs, GaAs, and AlGaAs₂ semiconductor by using the first-principles calculations. The chalcopyrite AlGaP₂, AlGaAsP, and AlGaAs₂ compounds have a semiconductor characters with a small band-gap. The interaction between Mn-3d and As-4p states at the Fermi level dominate rather than the other states. The ferromagnetic ordering of dopant Mn with high magnetic moment is induced due to the Mn(3d)-As(4p) strong coupling, which is attributed by the partially filled As-4p bands. The holes are mediated with keeping their 3d-electrons, therefore the ferromagnetic state is stabilized by this double-exchange mechanism. We noted that the ferromagnetic state with high magnetic moment is originated from the hybridized As(4p)-Mn(3d)-As(4p) interaction mediated by the holes-carrier.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.73-80
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• 1996

The single crystal growth has been carried out with the newly designed 1-T HB(single temperature zone horizontal Bridgman) system for GaAs crystals of 2 inch diameter doped with Si, Zn or undoped. With this method, incidence probability of single crystallinity was shown to be 0.73. Lattice defects evaluated from EPD(etch pit density) measurement were in the range of 5,000-20,000/cm2, dependent upon the doping condition. For the undoped GaAs crystals, carrier concentrations from the Hall measurement were ∼1×1016/cm3 at the seed part, which were less than half the concentrations of double of triple temperature zone(2-T, 3-T) HB grown crystals. By the 1-T HB method, therefore, GaAs crystals can be grown successfully with better yield and higher purity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.357-357
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• 2008

Spin injection experiment is conducted in epitaxially grown Fe/GaAs hybrid structure. For the formation of Schottky tunnel barrier between Fe and GaAs layers, highly n-doped GaAs layers are grown after n-doped channel layer. A non-local measurement, a voltage measurement probes do not contain a charge current path, is used for detecting only the chemical potential differences by the spin transport. As a result, the dips that are nicely matched with antiparallel region are obtained.

• Proceedings of the IEEK Conference
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• 2000.11b
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• pp.13-16
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• 2000

A quantum-wire field effect transistor(QW-FET) using asymmetric double InGaAs channel and Si-delta doped barrier has been fabricated. It exhibited good modulation and saturation characteristic in the range of ${\mu}\textrm{A}$ current level. For estimated channel width of 150nm QW-FET, maximum transconductance was about 400 mS/mm which is higher than a conventional heterostructure FET(HFET) with the same epi-structure.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.79-85
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• 1990

Monte Carlo simulation of hot-electron transport in $Al_{0.48}In_{0.52}As/Ga_{0.47}In_{0.53}$ As modulation-doped structure has been performed in which the nonparabolicity in $\Gamma$ valley is taken into account. The calculated results show that the inclusion of the nonparabolicty effect results in a huge decrease in drift velocity.

• Journal of Korean Vacuum Science & Technology
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• v.4 no.1
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• pp.27-32
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• 2000

We have studied the carrier relaxation of InAs/GaAs modulation-doped quantum dots depending on the excitation wavelength and modulation-doping concentration by using the time-ressolved spectroscopy. At the excitation below GaAs barrier band gap, the relaxation processes become very slow, implying to observe the phonon bottleneck effects. On the other hand, at the excitation far above GaAs band gap, phonon bottleneck effects are broken down due to Auger processes. Increasing modulation-doping concentration, the relaxation times, by virtue of Coulomb scattering between electrons in GaAs doped layer and carriers in InAs quantum dots, are observed to become fast.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.2
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• pp.75-78
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• 2009

Si-doped GaAs single crystals were grown by vertical gradient freeze using PBN crucibles. The amount of oxide layer $B_{2}O_{3}$ in PBN crucible was changed($0{\sim}0.2wt%$) and measured the concentration of carriers. The segregation coefficients of Si in GaAs melt decreased rapidly from initial 0.1 to 0.01 as the amount of $B_{2}O_{3}$ increases. At the same time, concentration of carriers was shown to decrease. It is likely that the reaction between dopant Si and $B_{2}O_{3}$ in GaAs melt results in the reduction of Si dopants(donor) while increase in the amount of boron(acceptor). The thin layer of $B_{2}O_{3}$ glass in PBN crucible was proved to be a better way to reduce defect formation rather than the total amount of $B_{2}O_{3}$.

• Korean Journal of Materials Research
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• v.29 no.9
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• pp.542-546
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• 2019

We investigate the characteristics of self-assembled quantum dot infrared photodetectors(QDIPs) based on doping level. Two kinds of QDIP samples are prepared using molecular beam epitaxy : $n^+-i(QD)-n^+$ QDIP with undoped quantum dot(QD) active region and $n^+-n^-(QD)-n^+$ QDIP containing Si direct doped QDs. InAs QDIPs were grown on semi-insulating GaAs (100) wafers by molecular-beam epitaxy. Both top and bottom contact GaAs layer are Si doped at $2{\times}10^{18}/cm^3$. The QD layers are grown by two-monolayer of InAs deposition and capped by InGaAs layer. For the $n^+-n^-(QD)-n^+$ structure, Si dopant is directly doped in InAs QD at $2{\times}10^{17}/cm^3$. Undoped and doped QDIPs show a photoresponse peak at about $8.3{\mu}m$, ranging from $6{\sim}10{\mu}m$ at 10 K. The intensity of the doped QDIP photoresponse is higher than that of the undoped QDIP on same temperature. Undoped QDIP yields a photoresponse of up to 50 K, whereas doped QDIP has a response of up to 30 K only. This result suggests that the doping level of QDs should be appropriately determined by compromising between photoresponsivity and operating temperature.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.389-392
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• 1987

The energy gaps of undoped and Cr doped GaAs and $Al_{0-3}Ga_{0-7}As$ was measured nondestructively using surface acoustic wave (SAW) technique. The result is good agreement with other reported result. This technique is inexpensive and simple one for the measurement of mole fraction of $Al_xGa_{1-x}As$.