The Synthesis Of ZnSe Crystals By Solvothermal Method

With the development of technology, semiconductor nanomaterials with excellent optical, electrical, magnetic properties in application in future research have aroused the interests of scientists around the world. As one of important II-VI semiconductor materials, with a direct band gap ( Eg = 2.67 eV ), zinc selenide in the solar cell, semiconductor optoelectronic devices, piezoelectric materials laser, and humidity sensors has very broad application prospects.The relationship between the structure and property of materials is very significant. Precisely controlling the sizes, dimensionalities, compositions, and crystal structures at nanoscaled level may be critical for the property improvement of materials and provide experimental basis for further systematic research. Currently, in the synthetic methods of zinc selenide nanomaterials, solvothermal method has been most widely used because of simple equipments and easy operation.In this work, two kinds of zinc selenide microstructures, zinc selenide hollow microspheres and zinc selenide plates, have been synthesized successfully via a solvothermal route. A series of analytical techniques, such as: scanning electronic microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and photoluminence (PL), were applied to characterizing the composition and morphology of the samples, and the growth mechanism was then analyzed.(1) The ZnSe hollow microspheres with cubic zinc blende structures were successfully synthesized by solvothermal reaction at 170℃for 48 h using Se powder and ZnSO4·7H2O as source materials, triethanolamine, water mixed solution as reaction medium, and KBH4 as reductant. Meanwhile, the growth mechanism of ZnSe hollow microspheres with a shell of the thickness about 100nm was analyzed. Based on the experimental results, the roles of water in solvent and bubbles produced from KBH4 during the reaction, as well as the effects of different Se sources were analyzed.(2) ZnSe plate structures were synthesized via a solvothermal method from zinc and selenium with ethylenediamine as ligand solvent. Through characterizing the morphology and structure of the samples, the results show that ZnSe plates have the hexagonal structure with a [1 01?0] growth direction and a thickness about 200-300nm. Furthermore, the formation mechanism of ZnSe plate structures is also discussed. And based on the above results, the effect of adding hydrazine hydrate on ZnSe plate shape structure was analyzed.