Investigation of Focused Ion and Electron Beam Platinum Carbon Nano-Tips with Transmission Electron Microscopy for Quantum Tunneling Vacuum Gap Applications

Abstract

To realize quantum tunneling applications with movable electrodes, sharp tips with radii down to several tens of nanometers are necessary. The use of a focused ion beam (FIB) and focused electron beam (FEB) with a gas injection system (GIS) allows the integration of geometries in the nanoscale directly into micro and nano systems. However, the implementation of the tunneling effect clearly depends on the material. In this work, a metal-organic precursor is used. The investigation of the prepared tunneling electrodes enables an insight into FIB/FEB parameters for the realization of quantum tunneling applications. For this purpose, a high-resolution transmission electron microscopy (HRTEM) analysis is performed. The results show a dependence of the material nanostructure regarding platinum (Pt) grain size and distribution in an amorphous carbon matrix from the used beam and the FIB currents. The integration of the tips into a polysilicon (PolySi) beam and measuring the current signal by approaching the tips show significant differences in the results. Moreover, the approach of FEB tips shows a non-contact behavior even when the tips are squeezed together. The contact behavior depends on the grain size, proportion of platinum, and the amount of amorphous carbon in the microstructure, especially at the edge area of the tips. This study shows significant differences in the nanostructure between FIB and FEB tips, particularly for the FIB tips: The higher the ion current, the greater the platinum content, the finer the grain size, and the higher the probability of a tunneling current by approaching the tips.

Ultra-Low Loaded Platinum Bonded Hexagonal Boron Nitride as Stable Electrocatalyst for Hydrogen Generation

“…The calculated inter-planar distance is found to be 1.4 Å, indicating the crystallographic (220) plane of Pt. 27 The powder XRD pattern (figure 2a) shows the specific Pt and BN planes as expected, with the 220 plane being of highest intensity for Pt, which also matches to the lattice plane distance observed in the HRTEM data. 28,29 The Pt crystalline peaks are broader in hBN_Pt than the previously reported Pt nano hBN, indicating the size reduction of Pt in hBN_Pt (Figure S2).…”

Use of PtC Nanotips for Low-Voltage Quantum Tunneling Applications

“…In addition, a study comparing several PtC tips by FIBID and FEBID using HRTEM analysis by Haub et al [ 22 ] leads to the recommendation to use a high current FIBID process to obtain a high tunneling suitability of PtC nanotips. In particular, the FEBID tips show small Pt grains and large spacing between the particles.…”

“…In addition, the PtC tips are applied to a HOPG sample in an STM. An HRTEM (high-resolution transmission electron microscopy) analysis about PtC nanotips is extensively discussed elsewhere by Haub et al [ 22 ]. The study comparing several PtC tips by FIBID and FEBID using HRTEM analysis by the authors shows significant differences in the nanostructure regarding the location, size, and distribution of the Pt particles.…”