Synthesis And Properties Of One-dimensional CdS Nanowire Arrays

Nano materials are a kind of ultrafine material with a magnitude of nanometer(1nm=10^-9m). Nano materials are currently a hot spot of research in materials science, andhavebroad applicationprospect forit's series ofnovel physics andchemical properties. But,itisstillachallengingtopicthathowtosynthesizecontrollablesizeandlowcostnanometermaterials through a great deal of experiments. It is also the necessary precondition for thewidespread use of nanometer materials. So, the study for the growth , preparation andcharacteristicsofnanomaterialsisofgreatsignificance.In recent years, Cadmium Sulphide (CdS) nano semiconductor material has beenwidely considered by many research groups in the world not only for its piezoelectricproperty but also its excellent physical and optoelectrical properties,which is aⅡB -Ⅵgroup compound with an energyband gap of about 2.42 eV. In this paper, one-dimensionalCadmium Sulphide (CdS) nanowire arrays were successfully synthesized in a sealedreaction kettle by using simple hydrothermal synthesis method. The sealed reaction kettlewas filled with thiosemicarbazide, Cd foils and ethylenediamine used as the S source, Cdsource and template agent, respectively. This synthesis method has series of advantages forthepreparationofone-dimensionalCadmiumSulphide(CdS)nanowirearrays,suchasgoodrepeatability,lowgrowthtemperatureandsoon. Meanwhile,theinfluencesofreactiontimeaswellasalkalinesolutionconcentrationonthemorphologyofCdShavebeeninvestigated.It shows that different lengthandsurfacetovolum ratioofthesamples canbecontrolledbyadjustingexperimentalparametersi.e.solutionconcentrationandreactiontime.Qualities and topography of these synthesized samples have been characterized byusing testing techniques of X-ray diffraction (XRD), scanning electron microscopy (SEM)and photoluminescence (PL) analysis. The results show that these samples are pureCadmium Sulphide (CdS) with a Alpha type hexagonal phase under this preparationcondition. The diameter and the length of Cadmium Sulphide (CdS) nanowire is about 200nm and several tens microns, respectively. The results of PL spectrums tested by usingHelium-Cadmium laser show that a strong intrinsic green emission band with a maximumaround 512 nm has been observed at room temperature. Meanwhile, it can be found thatethylenediamine solution concentration has a influence on the PL characteristics ofCadmiumSulphide(CdS).In this thesis, models of piezoelectric nanogenerator with different length and surfaceto volume ratio Cadmium Sulphide (CdS) nano array samples synthesized under abovedpreparation condition are assembled respectively. Output current of these models are testedand analyzed. These models of piezoelectric nanogenerator are driven by ultrasonic. The mechanism ofpower generation is also analyzed. Theresults show that the increasedlengthand enhanced surface to volume ratio of Cadmium Sulphide (CdS) nano arraysamples willhelp to improve the output efficiency of piezoelectric nanogenerator.At the same time, a new-style Cadmium Sulphide (CdS) nanogenerator ismanufactured for the first time,which is driven by high frequency electromagnetic radiationsignal i.e. alternative electromagnetic field. Output current of these models assembled withdifferent length and surface to volume ratio Cadmium Sulphide (CdS) nano array samplesaretested andanalyzed. Theeffects of angleand distancebetweenthesignal source andthemodel to the output current of the new model are also studied. In addition, The mechanismof power generation is analyzed,too.For its excellent physical and optoelectrical properties,one dimensional CdS nanostructures have been commonly applied in optoelec tronicdevicesfield,suchassignaldetection,sensors,andMEMSetc.