Synthesis And Characterization Of ZnE (E=S, Se, Te) And Mn-doped AlN Nanostructures

Wide band gap semiconductor nanomaterials have drawn universal attention due to their unique physicochemical properties and important applications, while controlled synthesis of nanomaterials is still the research hotspot in nanoscience. As wide and direct band gap II-VI semiconductor, ZnE (E=S, Se, Te) materials show great potential applications in laser and solar cell with the excellent optoelectronic and chemical performance. Diluted magnetic semiconductors (DMSs), combining the properties of both magnetic materials and semiconductors, have many potential applications for optical, electronic and magnetic devices. With a series of excellent optical properties and wide potential use, AlN nanostructure-based DMSs have important value in scientific research.The main work completed in this thesis can be summarized as following:1. This paper describes a novel ethanol amine (EA)-directed solvothermal approach for one-step synthesis of wurtzite-structured ZnS thin nanorods with mean diameters of about 6 nm adopting ZnO and Na₂S₂O₃·5H₂O as starting reagents. The as-prepared ZnS nanorods are well-crystallized single crystals with growth direction along [001] of wurtzite. The possible growth mechanism of the as prepared ZnS nanorods involving EA-mediated nucleation and one-dimensional (1D) growth has been discussed referring to the experimental results.2. Sphalerite or wurtzite ZnE (E=Se, Te) nanomaterials were synthesized by one-step solvothermal technique by using EA as solvent, zinc acetate as zinc source and Na₂EO₃ or E powder as E source. The test results show that sphalerite ZnE nanoparticles were obtained by adopting Na₂EO₃ as E source, and ZnE nanoplates with thickness of 60 nm by employing E powder as E source. Analysis indicates that EA solvent with appropriate coordination ability has played an important role in the formation of ZnE nanostructures, while the structure and morphology of ZnE nanomaterials are determined by the choice of E source.3. Mn-doped AlN single-crystalline nanorods, nanobelts and ultralong nanowires were grown on alumina and silicon substrates by doping Mn using a chemical catalyst-free vapor deposition method employing Al powder, anhydrous AlCl3, Mn powder, MnCl2 and NH3 as sources. Energy dispersive spectroscopy (EDS) and X-ray photoemission spectroscopy (XPS) demonstrate that Mn is successfully doped into the nanostructures. Ferromagnetic ordering of the AlN:Mn nanorods was observed both at 5 K and 300 K by a superconducting quantum interference device magnetometer (SQUID).4. Mn-doped AlN nanorod arrays and nanocrystalline films were synthesized on silicon plates and graphite sheets by adopting anhydrous AlCl₃, anhydrous MnCl₂ and NH3 as sources via a catalyst-free chemical vapor deposition method. Analysis shows that the as-prepared nanorods and nanocrystalline grow on the substrates with the alignment along [001] orientation of hexagonal AlN and ferromagnetic ordering of the Mn-doped AlN nanorod arrays was observed at 300 K by a SQUID.