Swelm Wageh, Al-Ghamdi Ahmed, Jilani Asim, Iqbal Javed
Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
Physics and Engineering Mathematics Department, Faculty of Electronic Engineering, Menoufia University, Menouf 32952, Egypt.
Nanomaterials (Basel). 2018 Nov 27;8(12):979. doi: 10.3390/nano8120979.
The synthesis of alloyed semiconductor quantum dots has produced structures that have distinct properties in comparison with both their bulk counterparts and their parent binary semiconductor quantum dots. In this work, the quantum confined structures of a ternary alloy of CdSeS were synthesized by one-pot synthesis method in an aqueous medium at a low temperature and capped with 3-mercaptopropoionic acid. Structures of the synthesized quantum dots were investigated by energy dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. The obtained quantum dots had modified cubic structures as proven by X-ray diffraction and selected area electron diffraction. The optical properties of the synthesized quantum dots were characterized by optical absorption, photoluminescence, and color analysis. Optical absorption investigation revealed a widening of the band gap of CdSeS with increasing S content. This widening increased for the samples suspended in water relative to the samples measured in powder form due to the difference in the environment of the two cases. The size determined from the optical absorption measurements was found to be compatible with the sizes obtained from the X-ray diffraction with the value of bowing parameter around 1, which indicated a graded diffusion of sulfur. It was also ascertained that the emission of different compositions covered the most visible range with a small full width at half maximum. The and values of the chromaticity coordinates decreased with increasing sulfur content of up to 15%, while the value increased.
合金半导体量子点的合成产生了与它们的体相材料及其母体二元半导体量子点相比具有独特性质的结构。在这项工作中，通过一锅法在水介质中低温合成了CdSeS三元合金的量子受限结构，并用3-巯基丙酸进行了封端。通过能量色散X射线、X射线衍射、X射线光电子能谱和高分辨率透射电子显微镜对合成的量子点结构进行了研究。X射线衍射和选区电子衍射证明，所获得的量子点具有改性的立方结构。通过光吸收、光致发光和颜色分析对合成量子点的光学性质进行了表征。光吸收研究表明，随着S含量的增加，CdSeS的带隙变宽。由于两种情况下环境的差异，相对于以粉末形式测量的样品，悬浮在水中的样品的这种变宽增加。从光吸收测量确定的尺寸与从X射线衍射获得的尺寸相符，弯曲参数值约为1，这表明硫的分级扩散。还确定不同组成的发射覆盖了最可见的范围，半高宽较小。随着硫含量增加到15%，色度坐标的x和y值降低，而z值增加。
