• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.1
• /
• pp.42-47
• /
• 2017

In this study, the physical and optical properties of $ZnS:Mn^{2+}$ Quantum Dot prepared by wet-process condition with Mn/Zn ratio was valuated. The powder characteristics and optical behavior were investigated through XRD, TEM and Photo spectrometer exicted by various UV light source. We found the main peak of ZnS (111) was shifted by 0.8 degree to low angle position with increasing stirring energy from 200 RPM to 600 RPM, which is thought to be the increase of lattice defects during wet process. The photo luminescence at 600 RPM shows also higher blue intensity which is well correlated with XRD results. With increasing Mn/Zn ratio, the PL intensity become higher and shifed by 8.5nm to right side, by the increment of substitutional $Mn^{2+}$ ions.

• Journal of the Korean Ceramic Society
• /
• v.55 no.1
• /
• pp.55-60
• /
• 2018

In this study, quantum dots composed of $Mn^{2+}$ doped ZnS core and ZnS shell were synthesized using MPA precursor at room temperature. The ZnS: Mn/ZnS quantum dots were prepared by varying the content of MPA in the synthesis of ZnS shells. XRD, Photo-Luminescence (PL), XPS and TEM were used to characterize the properties of the ZnS: Mn/ZnS quantum dots. As a result of PL measurement using UV excitation light at 365 nm, the PL intensity was found to greatly increase when MPA was added at 15 ml, compared to the case with no MPA; the PL peaks shifted from 603 nm to 598 nm. A UV sensor was fabricated by using a sputtering process to form a Pt pattern and placing a QD on the Pt pattern. To verify the characteristics of the sensor, we measured the electrical properties via irradiation with UV, Red, Green, and Blue light. As a result, there were no reactions for the R, G, and B light, but an energy of 3.39 eV was produced with UV light irradiation. For the sensor using ZnS: Mn/ZnS quantum dots, the maximum current (A) value decreased from $4.00{\times}10^{-11}$ A to $2.62{\times}10^{-12}$ A with increasing of the MPA content. As the MPA content increases, the PL intensity improves but the electrical current value dropped because of the electron confinement effect of the core-shell.