Influence of mn2 concentration and uv irradiation time on the luminescence properties of mn doped zns nanocrystals. The structure and particle size of the obtained powders were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and shown that all samples are single phase with sphalerite crystal structure and average particle size of about 5-7nm. | Communications in Physics, Vol. 19, No. 1 (2009), pp. 33-38 INFLUENCE OF Mn2+ CONCENTRATION AND UV IRRADIATION TIME ON THE LUMINESCENCE PROPERTIES OF Mn-DOPED ZnS NANOCRYSTALS TRAN MINH THI Faculty of Physics, Hanoi National University of Education Abstract. ZnS:Mn were prepared by wet chemical method with Mn doping concentration from 0 at% to 12 at%. The structure and particle size of the obtained powders were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and shown that all samples are single phase with sphalerite crystal structure and average particle size of about 5 - 7 nm. The dependence of Mn2+ ions doped concentration, and UV irradiation time on the luminescent intensity of ZnS:Mn nanocrystals was discussed. I. INTRODUCTION Zinc sulphide (ZnS) is an important II-VI semiconducting material with a wide direct band gap of eV in the bulk [1]. It has potential application in optoelectronic devices such as blue emitting diodes [2], electroluminescent devices and photovoltaic cells [3]. The optical properties of impurities, such as transition metal ion, doped ZnS have been the focus of several studies; in particular, of Mn2+ ions doped in ZnS nanocrystals. ZnS:Mn nanocrystals exhibit an orange luminescence with a high quantum efficiency under the interband excitation of the host crystals by utraviolet (UV) light. The 4 T1 → 6 A1 transition within the 3d5 configuration of the divalent manganese ion (Mn+2 ) has been studied extensively and its orange-yellow luminescence in ZnS is well documented. This luminescence was also observed in nanocrystalline ZnS:Mn2+ and applications have already been suggested [4-7]. It has been found that the amount of Mn2+ ions affected its luminescence intensity. Also, the PL intensity of ZnS:Mn nanocrystals was founded to increase under UV irradiation [8]. In this paper, we report on the effect of Mn-doped concentration and the dependence of UV irradiation time on the PL intensity of the ZnS:Mn .
