Physical mechanism of Au nanopore formation on pyramid using electron beam irradiation

Abstract

Recently there have been tremendous interests about the fabrication of the solid state nanopore due to its capability of the nanosize biosensor. In this report, the dynamics of the Au nanopore formation on the pyramidal membrane will be reported. The nanopores on the microfabricated Au coated SiO2 pyramid were fabricated using focused ion beam (FIB) and high energy electron beam techniques such as transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM). For high scanning electron beam irradiation using FESEM, shrinking of the Au nanopore was always observed. The nanopore formation dependent upon the primary electron voltage, and the scan rate of the FESEM electron beam was carefully examined. The higher closing rates for the faster scan rate and the lower electron accelerating voltage are observed. For the TEM electron beam exposure, the closing or the opening of the pore was observed depending upon the electron beam current. We do believe that this phenomenon can be attributed to the capillary force and the vaporization of the materials on the viscous liquid membrane due to TEM electron beam irradiation.