The influence of probe lift-up height on CNT electrical properties measurement under EFM DC mode

Abstract

Nowadays, one of the bottlenecks which hinder the development and application of carbon nanotube (CNT) nano device is that no pure semiconducting CNT (s-CNT) or metallic CNT (m-CNT) can be obtained, and for solving this problem scientists proposed some methods on preparation or separation, but all the results still should be detected and feedback to the process for further improving the preparation and separation methods. Thus, it is very important to measure and distinguish the electrical properties of CNT. For that, scientists proposed a method to measure CNT electrical properties based on DC electrostatic force microscope (EFM) mode, which distinguishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties. But, we discovered that the probe lift-up height will seriously affect the shape of the scan line, which makes this method not reliable in distinguishing m-CNT from s-CNT. In this paper, the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation, which will greatly improve the method of detecting CNT electrical properties by EFM.

Probing Polymorphic Stacking Domains in Mechanically Exfoliated Two-Dimensional Nanosheets Using Atomic Force Microscopy and Ultralow-Frequency Raman Spectroscopy

“…It decreased rapidly to 0.08 • when the lift height increased to 150 nm. By plotting the EFM phase shift as a function of the lift height, it can be observed that the phase shift of the MoS 2 nanosheets with different stacking domains decreased exponentially as the lift height increased (Figure S5 in SI), a result which aligns with the standard EFM response [70][71][72][73].…”