Study On Instability And Interaction Of Low-dimensional Nanosturcture As Athermally Induced By In-situ Electron Beam Irradiation In Transmission Electron Microscope

With the continuous development of nanotechnology,a variety of physical,chemical or biological methods for the fabrication of low-dimensional nanostructures(LDNs)have been developed.However,due to the intrinsic non-equilibrium nature of LDNs,most of these methods are unable to achieve precise control of the growth of LDNs.In order to break through this limitation and realize the functionalization of LDNs,non-equilibrium energetic beam nanoprocessing technology came into being.The electron beam(e-beam)in transmission electron microscopy(TEM)is the only energetic beam that can not only be used for the morphological and structural characterization of LDNs,but also for in-situ irradiation of LDNs.It plays an irreplaceable role in nanoprocessing or nanofabrication.In this paper,via TEM in-situ observation,we systematically studied the phenomenon of coalescence and passivation between LDNs as induced,by e-beam irradiation and explored the interaction mechanism caused by the instability of LDNs under the e-beam athermal activation.The main contents are as follow:1.The athermal interaction and coalescence between amorphous SiO_x nanowires(a-SiO_x NWs)in three different cases induced by e-beam irradiation were studied.First,the athermal interaction and coalescence process between two crossingly contacted a-SiO_x NWs were studied.Secondly,the athermal interaction and coalescence process among three crossingly contacted a-SiO_x NWs that are were studied.Finally,the athermal interaction and coalescence processes between two parallel-contacted a-SiO_x NWs were investigated.It is revealed that the near-surface atomic collective "diffusion" or plastic flow driven by the non-uniform distributed nanocurvature over the surface of the contacted nanowires and the e-beam athermal activation dominated the coalescence processes.2.The athermal interaction and coalescence between two contacted Au nanoparticles(NPs)induced by e-beam irradiation were studied.It revealed the corresponding relation between the surface atom transportation(i.e.,the surface atomic diffussion,plastic flow,and wetting effect)as well as the alignment rotation of the crystal orientation and the nanoparticle interface structure changes(especially the climb and slip of the interface misfit dislocation at room temperature),which is driven by the non-uniform distributed nanocurvature over the surface of the contacted nanoparticles and the e-beam athermal activation3.The structural instabilities of a-SiO_x NWs with and without unilaterally decorated by crystalline Au NPs induced by e-beam irradiation were studied.It is confirmed that the crystalline Au NP has passivation effect on the structural instability of the a-SiO_x NW over the side where the Au NPs were decorated.Therefore,it is revealed that the nanocurvature effect and the electron beam athermal activation effect of crystalline metal nanoparticles are weaker than these of amorphous nanowire.The overal study on the interaction of the LDNs in the above three different cases further confirms that the nanocurvature effect and the energetic beam athermal activation effect are the universal concepts for prediction and explanation of the energetic beam-induced structual instability of LDNs.It thus reveals the non-equilibrium,disordered(amorphous-like),nonlinear nature of the nanocurvature effect and the energetic beam athermal activation effect.At the same time,it also revealed that there is a big difference between the nanocurvature effect and the energetic beam athermal activation effect on crystalline(especially crystalline metallic)LDNs and those of amorphous LDNs.