Abstract

In the present study, undoped and Mn-doped ZnS, Zn_{1 – x}Mn_xS (x = 0, 0.02, 0.06, 0.10) quantum dots (QDs) were successfully synthesized using the simple co-precipitation method. The synthesized samples were thoroughly studied using X-ray diffraction (XRD), UV-visible absorption, high-resolution transmission electron microscopy (HRTEM) with selected area of the electron diffraction, scanning electron microscope with energy dispersive X-ray spectra, photoluminescence emission (PLE), and Fourier transform infrared spectroscopy. The XRD pattern confirmed the cubic zinc-blende phase at low doping concentration; however, at higher Mn-doping concentration hetaerolite phase formation was observed. The calculated particle size using Debye–Scherrer relation was found between 1.90–2.35 nm, which was also confirmed by HRTEM analysis. The blue shift in the absorption peak of all the prepared ZnS QDs as compared to bulk ZnS was indicative of the formation of nanoparticles and the calculated band gap was in the range of 3.94–4.11 eV. The PLE spectroscopy of the synthesized QDs was performed at the excitation wavelength of 280 nm and corresponding emission spectroscopy confirmed the surface defects in synthesized ZnS QDs.

中文翻译：

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锰掺杂的ZnS量子点：最佳掺杂量的研究

摘要

在本研究中，未掺杂和锰掺杂的ZnS，Zn _{1 – x} Mn _x S（x使用简单的共沉淀方法成功合成了= 0、0.02、0.06、0.10）个量子点（QD）。使用X射线衍射（XRD），紫外可见吸收，高分辨率透射电子显微镜（HRTEM）和选定的电子衍射区域，扫描电子显微镜以及能量色散X射线光谱，光致发光发射对合成的样品进行了深入研究（PLE）和傅立叶变换红外光谱。XRD图谱证实了低掺杂浓度下的立方-闪锌矿相。然而，在较高的Mn掺杂浓度下，观察到了辉铁矿相的形成。使用Debye-Scherrer关系式计算得出的粒径在1.90-2.35 nm之间，这也通过HRTEM分析得到了证实。与整体ZnS相比，所有制备的ZnS QD的吸收峰中的蓝移表示纳米颗粒的形成，计算出的带隙在3.94–4.11 eV的范围内。合成量子点的PLE光谱是在280 nm的激发波长下进行的，相应的发射光谱证实了合成ZnS量子点的表面缺陷。