科研之友
微信
新浪微博
Facebook
分享链接
摘要
We report the influence of electron-beam (E-beam) irradiation on the structural and physical properties modification of monolayer graphene (Gr), reduced graphene oxide (rGO) and graphene oxide (GO) with ultradispersed diamond (UDD) forming novel hybrid composite ensembles. The films were subjected to a constant energy of 200keV (40nA over 100nm region or electron flux of 3.9x10(19)cm(-2)s(-1)) from a transmission electron microscope gun for 0 (pristine) to 20min with an interval of 2.5min continuously - such conditions resemble increased temperature and/or pressure regime, enabling a degree of structural fluidity. To assess the modifications induced by E-beam, the films were analyzed prior to and post-irradiation. We focus on the characterization of hierarchical defects evolution using in situ transmission electron microscopy combined with selected area electron diffraction, Raman spectroscopy (RS) and Raman mapping techniques. The experiments showed that the E-beam irradiation generates microscopic defects (most likely, interstitials and vacancies) in a hierarchical manner much below the amorphization threshold and hybrids stabilized with UDD becomes radiation resilient, elucidated through the intensity, bandwidth, and position variation in prominent RS signatures and mapping, revealing the defects density distribution. The graphene sheet edges start bending, shrinking, and generating gaps (holes) at similar to 10-12.5min owing to E-beam surface sputtering and primary knock-on damage mechanisms that suffer catastrophic destruction at similar to 20min. The microscopic point defects are stabilized by UDD for hybrids in the order of GO>rGOGr besides geometric influence, i.e. the int erplay of curvature-induced (planar vs curved) energy dispersion/absorption effects. Furthermore, an attempt was made to identify the nature of defects (charged vs residual) through inter-defect distance (i.e. L-D). The trends of L-D for graphene-based hybrids with E-beam irradiation implies charged defects described in terms of dangling bonds in contrast to passivated residual or neutral defects. More importantly, they provided a contrasting comparison among variants of graphene and their hybrids with UDD.
- 出版日期2015-6
