【摘要】 用超声的方法合成了硒纳米线.场发射扫描电镜(FESEM)结果表明产物的形貌比较均一.产物的结构通过透射电镜(TEM)和X-射线衍射仪(XRD)进行了进一步表征.TEM和XRD光谱的结果证明了所得硒纳米线为单晶结构且沿着[001]方向生长.所得硒纳米线在671nm处有一紫外光谱吸收峰,通过对光谱的计算,硒纳米线的能带为1.66eV.基于一系列的生长过程,提出了硒纳米线的生长机理:硒粉溶解溶液中产生自由硒原子;当硒原子浓度过高时,硒原子结晶形成t型硒种子;由于各向异性晶体结构,连续提供的硒原子进入结晶种子形成线性纳米结构.此外,溶解和再结晶使α型硒转化为更稳定的t型硒.超声波可以提供适当的能量来调整这动态的平衡溶解和再结晶,进一步加快这一转变.更多还原

【Abstract】 In this paper,the selenium nanowires were synthesized with the sonochemical approach.The result of field-emission scanning electron microscopy(FESEM)shows that the as-prepared selenium nanowires are relatively uniform and abundant.Transmission electron microscopy(TEM)and X-rays diffraction(XRD)were further adopted to characterize the structure of the as-prepared Se products.The results of high-resolution TEM and XRD prove that the as-prepared selenium nanowires are single crystalline in nature and [001] oriented.The UV-vis absorption spectra of the selenium nanowires is determined at 671 nm,and the calculated forbidden energy gap is 1.66 eV.Based on a series of growth processes,a possible growth mechanism of the selenium nanowires was also proposed as follows:Se powders dissolve in the solution and generate free selenium atoms;then,selenium atoms recrystallize and form crystalline t-Se nuclei when the concentration of selenium atoms is high enough;the continuous feeding of selenium atoms onto the crystalline seeds leads to the formation of linear nanostructures due to the anisotropic crystal structure.In addition,the dissolution and sequential recrystallization make α-Se transform into more stable t-Se.Ultrasonic can provide proper energy to adjust the dynamics equilibrium of dissolution and recrystallization,thus accelerate its transformation.更多还原