Zinc Sulfide (ZnS) is one of the most widely used Ⅱ-Ⅵ inorganic semiconductor materials with a direct wide bandgap of 3.77eV for wurtzite phase and 3.72eV for cubic phase. Due to their excellent luminescence and physical properties, they have been used for sensors, light emitting diodes (LEDs) and lasers. In this regard, many researchers have tried to synthesize one-dimensional (1D) ZnS nanostructures, such as nanorods, nanowires, nanobelts, nanoribbons and nanotubes. In the present work, we have studied the 1D ZnS nanostructures prepared at various growth temperatures employing thermal chemical vapor deposition (Thermal CVD) system. The powder of zinc sulfide (ZnS), copper (Cu) and manganese (Mn) were used as the starting material and gold (Au) thin films were introduced as the catalytic promoter for the growth of nanowires. In this thermal evaporation process, the reaction temperature and staring materials played crucial roles for the formation of 1D ZnS nanostructures. The growth temperature and starting materials were found to be the main factors to define the morphology of the 1D ZnS nanostructures. The morphology, element analysis and phase structure were studied using high-resolution field emission scanning electron microscopy (HR FE-SEM), and x-ray diffraction (XRD). The XRD confirmed the phase present in the ZnS. The luminescence properties of 1D ZnS nanostructures were investigated by cathodoluminescence (CL) system. ⓒ 2017 DGIST
Table Of Contents
I. Introduction 1-- 1.1 Motivation 1-- 1.2 Literautre reviews 8-- II. EXPERIMENTAL DETAILS 10-- 2.1 Synthesis of ZnS nanostructures 10-- 2.1.1 Chemical vapor deposition 10-- 2.2 Experimental method 13-- 2.2.1 Experimental materials 13-- 2.2.2 Preparation of catalytic layer on substrate 13-- 2.2.3 Synthesis of un-doped / doped ZnS nanostructures 16-- 2.3 Characterizations 19-- 2.3.1 X-ray diffraction (XRD) 19-- 2.3.2 Electron microscopy (EM) 21-- 2.3.3 Cathodoluminescence (CL) 25-- III. RESULT AND DISCUSSION 26-- 3.1 Deposit rate of the Au catalytic layer 26-- 3.2 Morphology 26-- 3.3 Structural properties 31-- 3.4 Luminescence properties 33-- IV. CONCLUSIONS 36