ZnS:Er量子点材料制备及其受激发光特性研究

Fabrication and Luminescene Properties of ZnS:Er Quantum Dots Material Pumped by 980 nm LD

在水性介质中,制备了ZnS:Er量子点,并对其的X射线(XRF)谱、X射线衍射(XRD)谱、透射电子显微镜(TEM)图像和光致发光(PL)谱进行了研究,确定了所制备的ZnS:Er量子点材料中Er的浓度,观测到ZnS:Er量子点呈粒径为4nm的近球型结构。利用LD激发,在LD不同电流强度下得到ZnS:Er量子点从波长1500nm到1650nm的宽谱发射,并随着电流强度的增加ZnS:Er量子点的发射强度明显增加,当电流强度达到1.5A时,1545nm波长处的发射峰更明显。

We synthesized ZnS： Er doped quantum dots（QDs） in the aqueous medium from readily available precursors. The composition, construction, surface morphology and luminescence properties of the Er doped QDs were evaluated by XRF,TEM,XRD and emission spectra. The average particle size was calculated to be 4 nm,using the Scherrer formula which is in excellent agreement with that obtained from the TEM micrography. The LD fiber laser at 976±2 nm was utilized as the excitation source. The PL spectra with the broadband extending from 1. 500 to 1, 650 μm, is attributed to the intra-4f transition between the first excited state （^4 I13/2） and the ground state （^4 I15/2） of Er^3＋ at room temperature. It also shows that photoluminescence intensity increases with the increasing energy of excitation source. Er doped QDs have a wider and flatter fluorescence spectrum at 1. 500 μm region. It is because that the energy levels of Er^3＋ is split by a Coulomb interaction between electrons that includes the spin correction and spin-orbit coupling, and eventually by the Stark effect due to ZnS QDs crystal field and local coordination.