Synthesis PbS Nanocrystals In The Glass Matrix By A Melting Method

Nanocrystal materials develop rapidly in recent years. In the range ofsmall nanometer sizes, PbS nanocrystals of semiconductor have goodabsorption and emission in the near-infrared communication band (1.31.55μm). In addition, the glasses doped with the quantum dots havespecial properties, including chemical stability, thermal stability, shortresponse time, high nonlinear susceptibility and strong advantages inoptoelectronic and optical devices over the conventional devices. Therefore,is significant to study how to directly produce the PbS nanocrystals inthe glass matrix which are gain media for fiber lasers and fiber amplifiersdoped with quantum dots used in the optical communication.In this thesis, we focus on the synthesis of PbS nanocrystals in theglass matrix by using the melting method. PbS quantum dots obtained inthe experiment are verified in a X-ray diffraction (XRD), a high resolutiontransmission electron microscopy (TEM), a near infrared absorption spectroscopy. The PbS nanocrystals in size of 6~10 nm fabricated in themelting method are obtained by temperature down slowly from the glassmelting point to a room temperature, Unfortunately, the PbS nanocrystalsare agglomerated in local region. Then, we study the difference of thesynthesis of PbS nanocrystals prepared in the different glass, and analyzeeffects on the sizes of nanocrystals according to the dopants (PbO, S andPbS) and the doping concentrations. It first mentions to control reducingtemperature slowly after melting, which can be easier to crystallization PbSnanocrystals than conventional melting method. But also show somedeficiencies, for example, non-control of the particle sizes, particleagglomerations and the non-even particle distributions.