• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.377-385
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• 1996

ZnS/ZnSe superlattices were prepared on GaAs (100) substrates by hot wall epitaxy, an the structures were analyzed using x-ray diffraction. It is shown that the x-ray diffraction of the strained superlattice gives very useful information about the thickness of each layer, strain, interdiffusion, and the fluctuation of the superlattice period. Interdiffusion length of the S and Se is estimated to be less than $2\;{\AA}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.6
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• pp.467-471
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• 2000

The thermal annealing effect of $Zn_{0.9}Cd_{0.1}$ single quantum-well structures grown by molecular beam epitaxy is investigated. As the results of before and after rapid thermal annealed samples a red shift of E1-HH1 peak by Cd interdiffusion during thermal annealing of ZnCeSe/ZnSe sample was observed. In the case of annealed sample over $450^{\circ}C$ donor and acceptor impurities related peaks were observed which seems to be due to a diffusion of Ga and As from GaAs substrate. And also interdiffusion phenomena is idenified by the results of DCX measurements and which are consisten with the PL measurements.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.271-275
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• 1997

We have successfully grown Cl-doped ZnSe epitaxial layers on GaAs(100) sub-strates by HWE using $ZnCl_2$ as a doping source. The Cl-doped ZnSe layers showed mirrorlike morphology and good crystallinity. It has been found that the layer exhibited an n-type conduction with low resistivity. The carrier concentration is, obtained about $10^{16}\textrm {cm}^{-3}$, where a resistivity reached 10 $\Omega \textrm {cm}$. The layer with an appropriate doping level exhibited blue photoluminescence at room temperature. The strong blue PL was obtained at the hall mobility of $100^2\textrm {cm}$/Vㆍsec.

• Laser Solutions
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• v.7 no.3
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• pp.47-50
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• 2004

In this research, we investigated the characteristic of $ZnS_{0.24}Se_{0.76}/GaAs$ heterostructure by using photoreflectance sprctroscopy(PR). The oscillations observed above the 1.43 eV range were attributed Franze-Keldysh effect. The interface electric filed of $GaAs/ZnS_{0.24}Se_{0.76}\;is\;2.153{\times}104\;V/cm$.

• Journal of Sensor Science and Technology
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• v.17 no.6
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• pp.437-446
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• 2008

Single crystalline ${ZnIn_2}{Se_4}$ layers were grown on thoroughly etched semi-insulating GaAs (100) substrate at $400^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating ${ZnIn_2}{Se_4}$ source at $630^{\circ}C$. The crystalline structure of the single crystalline thick films was investigated by the photoluminescence (PL) and Double crystalline X-ray rocking curve (DCRC). The carrier density and mobility of ${ZnIn_2}{Se_4}$ single crystalline thick films measured from Hall effect by van der Pauw method are $9.41{\times}10^{16}cm^{-3}$ and $292cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the ${ZnIn_2}{Se_4}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)$=1.8622 eV-$(5.23{\times}10^{-4}eV/K)T^2$/(T+775.5 K). After the as-grown ${ZnIn_2}{Se_4}$ single crystalline thick films was annealed in Zn-, Se-, and In-atmospheres, the origin of point defects of ${ZnIn_2}{Se_4}$ single crystalline thick films has been investigated by the photoluminescence (PL) at 10 K. The native defects of $V_{Zn}$, $V_{Se}$, $Zn_{int}$, and $Se_{int}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Se-atmosphere converted ${ZnIn_2}{Se_4}$ single crystalline thick films to an optical p-type. Also, we confirmed that In in ${ZnIn_2}{Se_4}$/GaAs did not form the native defects because In in ${ZnIn_2}{Se_4}$ single crystalline thick films existed in the form of stable bonds.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.1
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• pp.45-54
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• 1998

본 연구에서는 열벽성장법에 의해 ZnSe 에피막을 GaAs 기판에 성장하고 double crystal x-ray diffractometer와 Photoluminescence (PL) 등의 장치를 이용하여 구조족, 광학 적 특성을 연구하였다. x-선 반치폭과 PL피크강도로부터 최적의 기판온도가 34$0^{\circ}C$임을 알 수 있었다. 또한 기판온도, 열벽부온도, 원료부온도, 성장시간등의 성장조건이 표면거칠기 성 장률, x-선 반치폭, PL 피크강도 등에 미치는 영향에 대하여 살펴보았다. 최적 성장조건하 에성장된 ZnSe 에피막의 x-선 반치폭은 149sec로 나타났는데 이는 HWE 성장법으로 성장 된 ZnSe 에피막에 대하여 보고된 수치 중 가장낮은 값이다. PL 스펙트럼에서 I2 피크와 DAP 피크의 강도는 높고, SA 피크의 강도는 낮다는 사실로부터 본 연구에서 성장된 ZnSe 에피막의 결정질이 매우 우수함을 확인하였다.

• Applied Microscopy
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• v.25 no.3
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• pp.75-81
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• 1995

The microstructural characterization of ternary $ZnS_{x}Se_{1-x}$(x=0.085) on GaAs(001) substrate grown up to $2{\mu}m\;at\;300^{\circ}C$ by molecular beam epitaxy(MBE) which has a single growth chamber was investigated by high resolution transmission electron microscope (HRTEM) working at 300 kV with point resolution of 0.18nm. The interface in the ZnSSe/GaAs specimen maintains a pseudomorphism with the substrate, but the epilayer has high density of stacking faults and moire fringes. The pits which had formed along <111> direction were found at the interface of ZnSSe/GaAs. The pits were responsible for producing defects in both epilayer and substrate. The wavy interface which has the difference of 15nm in height was found to maintain the pseudomorphism with the substrate and no stacking faults were found around the interface. However there exists faint and fine moire fringes in the epilayer near interface.

• Korean Journal of Materials Research
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• v.23 no.3
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• pp.183-189
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• 2013

$Cu_2ZnSn(S,Se)_4$ material is receiving an increased amount of attention for solar cell applications as an absorber layer because it consists of inexpensive and abundant materials (Zn and Sn) instead of the expensive and rare materials (In and Ga) in $Cu(In,Ga)Se_2$ solar cells. We were able to achieve a cell conversion efficiency to 4.7% by the selenization of a stacked metal precursor with the Cu/(Zn + Sn)/Mo/glass structure. However, the selenization of the metal precursor results in large voids at the absorber/Mo interface because metals diffuse out through the top CZTSe layer. To avoid the voids at the absorber/Mo interface, binary selenide compounds of ZnSe and $SnSe_2$ were employed as a precursor instead of Zn and Sn metals. It was found that the precursor with Cu/$SnSe_2$/ZnSe stack provided a uniform film with larger grains compared to that with $Cu_2Se/SnSe_2$/ZnSe stack. Also, voids were not observed at the $Cu_2ZnSnSe_4$/Mo interface. A severe loss of Sn was observed after a high-temperature annealing process, suggesting that selenization in this case should be performed in a closed system with a uniform temperature in a $SnSe_2$ environment. However, in the experiments, Cu top-layer stack had more of an effect on reducing Sn loss compared to $Cu_2Se$ top-layer stack.

• Applied Microscopy
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• v.25 no.3
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• pp.82-89
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• 1995

High resolution transmission electron microscopic observations on quaternary $Zn_{1-x}Mg_{x}S_y$ $S_{1-y}$(x=0.13, y=0.16) on (001) GaAs substrate grown up to $1.2{\mu}m$ with 20nm ZnSe buffer layer at $300^{\circ}C$ by RIBER MBE system which has a single growth chamber were investigated by HRTEM working at 300kV with point resolution of 0.18nm. The ZnSe buffer layer maintains the coherency with the GaAs substrate. The stacking faults had begun at ZnSe buffer/$Zn_{1-x}Mg_{x}S_{y}S_{1-y}$ interface, whose length and spacing became larger than 60nm and wider than 40nm, respectively. The inverse triangular stacking fault was bounded by stacking faults which were formed on {111} planes with different variants. There exists rare stacking faults inside the triangular defect. The epilayer surrounded by the straight stacking faults, which had formed in the same direction, became the columnar structure.

• Current Photovoltaic Research
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• v.8 no.3
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• pp.102-106
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• 2020

In this paper, the effect of MoSe₂ on the contact resistance (R_C) of the transparent conducting oxide (TCO) and Mo junction in the scribed P2 region of the Cu(In,Ga)Se₂ (CIGS) solar module was analyzed. The CIGS/Mo junction becomes ohmic-contact by MoSe₂, so the formation of the MoSe₂ layer is essential. However, the CIGS solar module has a TCO/MoSe₂/Mo junction in the P2 region due to structural differences from the cell. The contact resistance (R_C) of the P2 region was calculated using the transmission line method, and MoSe₂ was confirmed to increase R_C of the TCO/Mo junction. B doped ZnO (BZO) was used as TCO, and when BZO/MoSe₂ junction was formed, conduction band offset (CBO) of 0.6 eV was generated due to the difference in their electron affinities. It is expected that this CBO acts as a carrier transport barrier that disturbs the flow of current, resulting in increased R_C. In order to reduce the R_C caused by CBO, MoSe₂ must be made thin in a CIGS solar module.