One-Dimensional ZnSSe-ZnSe Axial Heterostructure And Applied For Photodetectors

One-dimensional semiconductor nanostructure materials,as the most basic structural unit in constructing of nano-integrated devices,have long been recognized as the foundation and important candidate for the next generation of nano-optoelectronic devices and integrated electronic systems.The semiconductor band gap is one of the most important parameters in the field of optoelectronics.It determines the emission and absorption characteristics of semiconductor nanomaterials.However,due to the very limited types of semiconductor band gaps in nature and the very few types of semiconductors in nature,it has caused a lot of inconveniences in the manufacture of devices by nanomaterials and in the application of these devices.Here,we use a special moving source materials Chemical Vapor Deposition method to synthesize group II-VI ZnS_0.49Se_0.51/ZnSe heterojunction semiconductor nanowires with different band gaps along a single nanowire and achieved an abrupt junction between the two materials with different bandgap..These ZnS_0.49Se_0.51/ZnSe heterojunction nanowires have band gaps ranging from about 2.7 to3.0 eV.The corresponding optoelectronic properties are systematically studied.The representative results are as follows:（1）ZnS nanowires and ZnSe nanowires were synthesized by chemical vapor deposition and Au as catalysts by changing the growth conditions on Si wafers.The samples were characterized by XRD and PL.The results show that the prepared ZnS and ZnSe nanowires have good crystallinity and properties,and the growth mechanism of ZnS and ZnSe nanowires is briefly discussed.（2）ZnS_0.49Se_0.51.51 nanowires were prepared by chemical vapor deposition of source.The ZnS_0.49Se_0.51.51 nanowire prepared by XRD and PL characterization has good crystallinity and luminescent properties.And the growth mechanism of ZnS_0.49Se_0.51nanowires was briefly discussed.（3）The ZnS_0.49Se_0.51/ZnSe heterojunction nanowires were synthesized by two-step synthesis using source mobile chemical vapor deposition.The characterization of SEM,PL,UV,XRD,TEM and XPS shows that the prepared heterojunction has good crystallinity,good morphology and luminescence properties.The grown ZnS_0.49Se_0.51/ZnSe heterojunction nanowires were fabricated into devices,which were found to have good optical responsivity and quantum efficiency,and have broad spectrum detection around 360 nm to 480 nm.