• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.24-27
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• 2004

ZnS nanoparticles were synthesized and doped with $Pr^{3+}\;and\;Mn^{2+}$. Photoluminescence(PL) peaks were observed at 430 nm for pure ZnS, 585 nm for $Mn^{2+}-doped$ ZnS, and at around 430, 460, 480, 495 nm for ZnS nanoparticles doped with $Pr^{3+}$, respectively. For co-doped sample, both characteristics of doping with each element were exhibited. Optical annealing through UV irradiation was carried out in the two atmospheres; air and vacuum. The increases of the luminescence intensity was more considerable in the air, which is attributed to the photo-induced oxidation. In the case of co-doped sample the change of the emission color was observed by UV annealing.

• Advances in materials Research
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• v.11 no.3
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• pp.225-235
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• 2022

It includes the synthesis of pristine ZnO nanoparticles and a series of Ag-doped zinc oxide nanoparticles was carried out by reflux method by varying the amount of silver (1, 3, 5, 7 and 9% by mol.). The morphology of these nanoparticles was investigated by SEM, XRD and FT-IR techniques. These techniques show that synthesized particles are homogenous spherical nanoparticles having an average particle size of about 50-100 nm along with some agglomeration. The photocatalytic activity of the ZnO nanoparticles and Ag doped ZnO nanoparticles were investigated via photodegradation of methylene blue (MB) as a standard dye. The data from the photocatalytic activity of these nanoparticles show that 7% Ag-doped ZnO nanoparticles exhibit much enhanced photocatalytic activity as compared to pristine ZnO nanoparticles and other percentages of Ag-doped ZnO nanoparticles. Furthermore, 7% Ag-doped ZnO was made composites with sulfur-doped graphitic carbon nitride by physical mixing method and a series of nanocomposites were made (3.5, 7.5, 25, 50, 75% by weight). It was observed that the 25% composites exhibited better photocatalytic performance than pristine S-g-C 3 N 4 and pure 7% Ag-doped ZnO. Tauc's plot also supports the photodegradation results.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.493-498
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• 1998

ZnS doped borosilicate glass for nonlinear optical application was prepared by melting and precipitation process. The optical band gap of the precipitated ZnS particles ranged from 3.83 to 3.96 eV compared with the bulk ZnS energy gap of 3.53 eV. This result was interpreted in terms of a quantum confinement effect due to small crystal size. ZnS partilcle size estimated by effective mass approximation ranged from about 39 to 83 $\AA$ It increased wtih the increase of heat tratment time and temperature.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.50-60
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• 1997

Undoped, cobalt-doped and erbium-doped $ZnAl_2S_4, ;ZnAl_2Se_4, ;CdAl_2S_4, ;and;CdAl_2Se_4$ single crystals were grown by the chemical transport reaction method. The crystal structures, the lattice constants, the optical energy gaps, and the photoluminescence properties of these single crystals were investigated. Also, the optical transition mechanisms by the impurities of cobalt and erbium were identified from these results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.414-414
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• 2008

Vertically well-aligned Ga-doped ZnO nanorods with different Ga contents were grown by thermal evaporation on a ZnO template. The Ga-doped ZnO nanorods synthesized with 50 wt % Ga with respect to the Zn content showed maximum compressive stress relative to the ZnO template, which led to a rapid growth rate along the c-axis due to the rapid release of stored strain energy. A further increase in the Ga content improved the conductivity of the nanorods due to the substitutional incorporation of Ga atoms in the Zn sites based on a decrease in lattice spacing. The p-n diode structure with Ga-doped ZnO nanorods, as a n-type, displayed a distinct white light luminescence from the side-view of the device, showing weak ultraviolet and various deep-level emissions.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.3
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• pp.313-318
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• 2005

Li-doped ZnS layers were grown by molecular beam epitaxy. It was found that relatively low growth temperature is suitable for effective incorporation of Li acceptors. The layers grown under optimized conditions exhibited photoluminescence spectra dominated by neutral-acceptor-bound excitons. Such layers also showed electrically p-type behavior in capacitance-voltage characteristics. The net acceptor concentration is estimated to be approximately $3{\times}10^{15}\;cm^{-3}$.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1337-1342
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• 1998

To investigate an effect of phase separation on precipitation characteristics of ZnS microcrystals in ma-trix glass ZnS doped borosilicate glasses for nonlinear optical applications were prepared by melting and pre-cipitation process. ZnS dopant contributed to phase separation promotion which increased the phase separa-tion of the matrix glass within immiscibility region. It was also found that ZnS as phase separation promoter showed a similar contribution for some selected glass compositions in miscibility region. The precipitation of ZnS microcrystals occurred in thephase separable glass compoitions. The radius of ZnS microcrystals in-creased with increasing the heat treatment temperature and Na2O contents of matrix glass composition. The ZnS particle sizes estimated by effective mass approximation ranged from about 30 to 80${\AA}$ It was suf-ficiently small to show quantum confinement effect.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.159-160
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• 2011

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.41.2-41.2
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• 2011

Display 산업의 확대로 인해 광학적 특성 및 전기적 특성이 우수한 TCO (Transparent conductive oxide) 연구가 활발히 진행되고 있다. 기존에는 ITO가 대부분의 분야에서 이용되었지만 In의 경제적인 단점으로 인해 새로운 대체물로써 ZnO가 떠오르고 있다. ZnO는 전형적인 n-type 반도체이며, wide band gap 물질로써 Al, Ga, B과 같은 3 족 원소를 doping 함으로써 광학적 및 전기적 특성을 향상시킬 수 있다. 최근에는 ZnO의 이온반경과 비슷한 Ga을 도핑한 Ga-doped ZnO 박막에 대한 연구가 활발히 진행되고 있다. 이는 ZnO에 Ga을 도핑함으로써 격자결함을 최소화 시키고 carrier concentration 및 hall mobility를 향상시켜 전기전도도의 향상을 이루기 때문이다. 본 연구에서는 $Ga_2O_3$이 3wt% doping 된 ZnO rotating cylindrical target 을 DC magnetron sputtering 을 이용하여 2 kW의 파워와 70 kHz의 주파수를 고정하고, 증착 온도를 변화시켜 유리 기판 위에 Ga-doped ZnO 박막을 증착 하였다. 증착 시 온도가 Ga-doped ZnO 박막에 미치는 영향을 관찰하기 위해 박막 표면의 조성을 분석하였고, 결정성 및 전기적 특성의 변화를 통해 박막의 특성을 비교 평가하였다. Ga-doped ZnO 박막의 표면과 두께는 SEM (Scanning electron microscope) 분석을 통해 관찰하였고, XRD (X-ray diffractometer) 를 이용하여 결정학적 특성을 확인하였다. 또한 Van der Pauw 방법을 이용한 hall 측정을 통해 resistivity, carrier concentration, hall mobility를 분석하였고, UV-Vis를 이용하여 박막의 투과율을 분석하였으며, 이를 토대로 투명 전도막으로써 Ga-doped ZnO 박막의 응용 가능성을 평가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.127-130
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• 2005

The properties of phosphorus doped ZnO multilayer thin films deposited on (001) sapphire substrates by pulsed laser deposition (PLD) were investigated by using annealing treatment at various annealing temperature after deposition. The phosphorus doped ZnO multilayer was composed of phosphorus doped ZnO layer and two pure ZnO layers on sapphire substrate. The structural. electrical and optical properties of the ZnOthin films were measured by X-ray diffraction (XRD). Hall measurements and photoluminescence (PL). As the annealing temperature optimized. the electrical properties of the ZnO multilayer showed a electron concentration of $1.56{\times}10^{16}/cm^3$, a resistivity of 17.97 ${\Omega}cm$. It was observed the electrical property of the film was changed by dopant activation effect as thermal annealing process