• Journal of Sensor Science and Technology
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• v.13 no.2
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• pp.157-167
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• 2004

A stoichiometric mixture of evaporating materials for $CuAlSe_{2}$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_{2}$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_{2}$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}cm^{-3}$ and $295cm^{2}/V{\codt}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$ = 2.8382 eV - ($8.68{\circ}10^{-4}$ eV/K)$T^{2}$/(T + 155 K). The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_{2}$ have been estimated to be 0.2026 eV and 0.2165 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_{5}$ states of the valence band of the $CuAlSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1-}$, $B_{1-}$, and $C_{1-}$ exciton peaks for n = 1.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.5
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• pp.179-186
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• 2007

Single crystal $CdGa_2Se_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with the hot wall epitaxy(HWE) system by evaporating the polycrystal source of $CdGa_2Se_4$ at $630^{\circ}C$. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of single crystal $CdGa_2Se_4$ thin films measured with Hall effect by van der Pauw method are $8.27{\times}10^{17}cm^{-3},\;345cm^2/V{\cdot}s$ at 293 K, respectively. The photocurrent and the absorption spectra of $CdGa_2Se_4/SI$(Semi-Insulated) GaAs(100) are measured ranging from 293 K to 10 K. The temperature dependence of the energy band gap of the $CdGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation $E_g(T)=2.6400eV-(7.721{\times}10^{-4}eV/K)T^2/(T+399K)$. Using the photocurrent spectra and the Hopfield quasicubic model, the crystal field energy(${\Delta}cr$) and the spin-orbit splitting energy(${\Delta}so$) far the valence band of the $CdGa_2Se_4$ have been estimated to be 106.5 meV and 418.9 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1^-},\;B_{1^-},\;and\;C_{11}-exciton$ peaks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.352-356
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• 2003

A stoichiometric mixture of evaporating materials for $CuGaSe_2$ single crystal am films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuGaSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.615\;{\AA}\;and\;11.025\;{\AA}$, respectively. To obtain the single crystal thin films, $CuGaSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $610^{\circ}C$ and $450^{\circ}C$, respectively, The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuGaSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;:\;1.7998\;eV\;-\;(8.7489\;{\times}\;10^{-4}\;eV/K)T^2(T\;+\;335\;K)$. After the as-grown $CuGaSe_2$ single crystal thin films was annealed in Cu-, Se-, and Ga-atmospheres, the origin of point defects of $CuGaSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{CU}$, $V_{Se}$, $CU_{int}$, and $Se_{int}$, obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuGaSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that Ga in $CuGaSe_2/GaAs$ did not form the native defects because Ga in $CuGaSe_2$ single crystal thin films existed in the form of stable bonds.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.111-112
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• 2005

To obtain the single crystal thin films, $CuInSe_2$, mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wail epitaxy (HWE) system. The source and substrate temperatures were 620$^{\circ}C$ and 410$^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobilily of $CuInSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.62\times10^{16}$ $cm^{-3}$ and $296cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the CulnSe$_2$ obtained from the absorption spectra was well described by the Varshni's relation E$_g$(T) = 1.1851 eV - ($8.99\times10^{-4}$ ev/K)T$_2$/(T + 153K). After the as-grown $CuInSe_2$ single crystal thin films was annealed in Cu-, Se-, and In-atmospheres the origin of point defects of $CuInSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The nat ive defects of V$_{Cu}$, $V_{Se}$, Cu$_{int}$, and $Se_{int}$ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuInSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that In in $CuInSe_2$/GaAs did not form the native defects because In in $CuInSe_2$ single crystal thin films existed in the form of stable bonds.

• Korean Journal of Crystallography
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• v.11 no.4
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• pp.212-223
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• 2000

A stochiometric mix of CuInTe₂ polycrystal was prepared in a honizonatal furnace. To obtain the single crystal thin films, CuInTe₂ mixed crystal was deposited on throughly etched GaAs(100) by the HWE system. The source and substrate temperatures were 610℃ and 450℃ respectively, and the thickness of the deposited single crystal thin film was 2.4㎛. CuInTe₂ single crystal thin film was proved to be the optimal growth condition when the excition emission spectrum was the strongest at 1085.3 nm(1.1424 eV) of photoluminescence spectrum at 10 K, and also FWHM of Double Crystal X-ray Rocking Curve (DCRC) was the smallest, 129 arcsec. The Hall effect on this sample was measured by the method of Van der Pauw, and the carrier density and mobility dependent on temperature were 9.57x10/sup 22/ electron/㎥, 1.31x10/sup -2/㎡/V·s at 293 K, respectively. The ΔCr(Crystal field splitting) and the ΔSo (spin orbit coupling splitting( measured at f10K from the photocurrent peaks in the short wavelength of the CuInTe₂ single crystal thin film were about 0.1200 eV, 0.2833 eV respectively. From the PL spectra of CuInTe₂ single crystal thin film at 10 K, the free exciton (E/sub x/) was determined to be 1064.5 nm(1.1647 eV) and the donor-bound exciton(D/sup 0/, X) and acceptor-bound exciton (A/sup 0/, X) were determined to be 1085.3 nm(1.1424 eV) and 1096.8 nm(1.1304 eV0 respectively. And also, the donor-acciptor pair (DAP)P/sub 0/, DAP-replica P₁, DAP-replica P₂ and self-activated (SA) were determined to be 1131 nm (1.0962 eV), 1164 nm(1.0651 eV), 1191.1 nm(1.0340 eV) and 1618.1 nm (0.7662 eV), respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.442-446
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• 2000

The metal-oxide-semiconductor field-effect transistor(MOSFET) has undergone many changes in the last decade in response to the constant demand for increased speed, decreased power, and increased parking density. Therefore, it was interested in scaling theory, and full-band Monte Carlo device simulator has been used to study the effects of device scaling on hot carriers in different MOSFET structures. MOSFET structures investigated in this study include a conventional MOSFET with a single source/drain, implant a lightly-doped drain(LDD) MOSFET, and a MOSFET built on an epitaxial layer(EPI) of a heavily-doped ground plane, and those are analyzed using TCAD(Technology Computer Aided Design) for scaling and simulation. The scaling has used a constant-voltage scaling method, and we have presented MOSFET´s characteristics such as I-V characteristic, impact ionization, electric field and recognized usefulness of TCAD, providing a physical basis for understanding how they relate to scaling.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.297-305
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• 2000

It is observed that the initial properties and degradation characteristics on plasma of n/p-MOSFET with polycide and poly-Si as different gate materials under F-N stress and hot electron stress are affected by metal AR(Antenna Ratio) during plasma process. Compared to that of MOS devices with poly-Si gate material, reliability properties on plasma of MOS devices with polycide gate material are improved. This can be explained by that fluorine of tungsten polycide process diffuses through poly-Si into gate oxide and results in additional oxide thickness. The fact that MOS devices with polycide gate material can reduce damages of plasma process shows possibility that polycide gate material can be used as gate material for next generation MOS devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.257-265
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• 2002

A stoichiometric mixture of evaporating materials for AgInS$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, AgInS$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy(HWE) system. The source and substrate temperatures were 680 $^{\circ}C$ and 410 $^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of AgInS$_2$ single crystal thin films measured from Hall effect by van der Pauw method are 9.35${\times}$10$\^$16/ cm$\^$-3/ and 294 $\textrm{cm}^2$/V$.$s at 293 K, respectively. From the optical absorption measurement, the temperature dependence of the energy band gap on AgInS$_2$ single crystal thin films was found to be E$\_$g/(T) : 2.1365 eV - (9.89 ${\times}$ 10$\^$-3/ eV) T$^2$/(2930 + T). After the as-grown AgInS$_2$ single crystal thin films was annealed in Ag-, S-, and In-atmospheres, the origin of point defects of AgInS$_2$ single crystal thin films has been investigated by using the photoluminescence(PL) at 10 K. The native defects of V$\_$AG/, V$\_$S/, Ag$\_$int/, and S$\_$int/ obtained from PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted AgInS$_2$ single crystal thin films to an optical p-type. Also, we confirmed that In in AgInS$_2$/GaAs did not form the native defects because In in AgInS$_2$ single crystal thin films did exist in the form of stable bonds.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.171-174
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• 2004

The stochiometric $AgGaSe_2$ polycrystalline mixture of evaporating materials for the $AgGaSe_2$ single crystal thin film was prepared from horizontal furnace. To obtain the single crystal thin films, $AgGaSe_2$ mixed crystal and semi-insulating GaAs(100) wafer were used as source material and substrate for the Hot Wall Epitaxy (HWE) system, respectively. The source and substrate temperature were fixed at $630^{\circ}C$ and $420^{\circ}C$, respectively. The thickness of grown single crystal thin films is $2.1{\mu}m$. The single crystal thin films were investigated by photoluminescence and double crystal X-ray diffraction(DCXD) measurement. The carrier density and mobility of $AgGaSe_2$ single crystal thin films measured from Hall effect by van der Pauw method are $4.89{\times}10^{17}\;cm^{-3},\;129cm^2/V{\cdot}s$ at 293K, respectively. From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the $AgGaSe_2$ single crystal thin film, we have found that the values of spin orbit splitting ${\Delta}S_o$ and the crystal field splitting ${\Delta}C_r$ were 0.1762 eV and 0.2494 eV at 10 K, respectively. From the photoluminescence measurement of $AgGaSe_2$ single crystal thin film, we observed free excition $(E_X)$ observable only in high quality crystal and neutral bound exciton $(D^o,X)$ having very strong peak intensity And, the full width at half maximum and binding energy of neutral donor bound excition were 8 meV and 14.1 meV, respectively. By Haynes rule, an activation energy of impurity was 141 meV.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.226-229
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• 2004

A stoichiometric mixture of evaporating materials for $CuAlSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;2.8382\;eV\;-\;(8.68{\times}10^{-4}\;eV/K)T^2/(T+155K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_2$ have been estimated to be 0.2026 eV and 0.2165 eV at 10K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $CuAlSe_2$. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.