Preparation Of ZnSe Nanomaterials And Research On Its Surface Enhanced Raman Scattering Mechanism

Surface enhanced Raman scattering(SERS)is an analytical detection technology that can provide single-molecule level biochemical detection and can detect trace molecules,which has important significance in biomedicine,food safety,environmental detection,national defense safety and other aspects.Semiconductor materials as SERS substrates are easier to achieve large-area,low-cost preparation compared to the precious metal substrates,and show excellent reproducibility,high uniformity,good anti-interference,anti-degradation,and excellent biocompatibility.From one-dimensional to three-dimensional semiconductor nanomaterials,one-dimensional semiconductor materials have a larger surface area to volume ratio.This special structural performance makes it have advantages such as lateral quantum confinement,which can promote the charge transfer between the substrate and the detection molecule,and improve the SERS performance.However,one-dimensional ZnSe nanomaterials are rarely reported inSERS research.Therefore,one-dimensional ZnSe nanomaterials with different morphologies were prepared onSi O₂/Si substrate by physical vapor deposition(PVD)method in this paper,and their structures and morphologies were systematically characterized.To obtain thedifferent morphologies,the growth temperature was changed during the growth process.Raman spectra of one-dimensional ZnSe nanomaterials with different morphologies were collected,which illustrate the changes of Raman shift and demonstrate the successful fabrication of one-dimensional ZnSe nanomaterials with different morphologies.Futhermore,rhodamine 6G(R6G)and crystal violet(CV)were chosen as the probe molecules to demonstrate SERS performance of one-dimensional ZnSe nanomaterials with different morphologies.The detail contents are as follows:(1)One-dimensional ZnSe nanomaterials with different morphologies were prepared by changing the growth temperature and using PVD method,and their structures and morphologies were characterized,proving the successful preparation of one-dimensional wurtzite ZnSe nanowires,sphalerite ZnSe nanobelts,twins crystal ZnSe with“saw blades-like”nanostructure.The successful preparation of one-dimensional ZnSe nanomaterials with different structures lay the foundation for the investigation of their SERS performance.(2)R6G was employed as the probe molecule to demonstrate the SERS enhancement effect of one-dimensional ZnSe nanometer materials with different structures,which illustrates the optimal SERS signal can be obtained from the twin ZnSe nanostructure.The SERS signals of the R6G and CV molecules adsorbed on twin-ZnSe nanowires could be easily detected even with an ultralow concentration of 10^-11mol/L and 10^-8 mol/L,respectively.Thus,the limit of detection is 10^-11 mol/L and 10^-8mol/L respectively.The corresponding enhancement factor(EF)were up to 6.12×10⁷and 3.02×10⁵,respectively.It was also proved that twin-ZnSe nanowires as SERS substrate has good homogeneity and reproducibility,indicating that one-dimensional ZnSe nanomaterials has a wide application prospect inSERS detection.(3)The charge transfer(CT)between the twin-ZnSe nanowires and R6G molecule has been demonstrated theoretically with first-principles calculations based on density-functional theory(DFT).This paper also presents the band diagrams of ZnSe nanomaterials and R6G to give a comprehensive overview of possible charge transfer paths and to prove the charge transfer mechanism.