Development and Application of Multiple‐Probe Scanning Probe Microscopes

Abstract

In the research of advanced materials based on nanoscience and nanotechnology, it is often desirable to measure nanoscale local electrical conductivity at a designated position of a given sample. For this purpose, multiple-probe scanning probe microscopes (MP-SPMs), in which two, three or four scanning tunneling microscope (STM) or atomic force microscope (AFM) probes are operated independently, have been developed. Each probe in an MP-SPM is used not only for observing high-resolution STM or AFM images but also for forming an electrical contact enabling nanoscale local electrical conductivity measurement. The world's first double-probe STM (DP-STM) developed by the authors, which was subsequently modified to a triple-probe STM (TP-STM), has been used to measure the conductivities of one-dimensional metal nanowires and carbon nanotubes and also two-dimensional molecular films. A quadruple-probe STM (QP-STM) has also been developed and used to measure the conductivity of two-dimensional molecular films without the ambiguity of contact resistance between the probe and sample. Moreover, a quadruple-probe AFM (QP-AFM) with four conductive tuning-fork-type self-detection force sensing probes has been developed to measure the conductivity of a nanostructure on an insulating substrate. A general-purpose computer software to control four probes at the same time has also been developed and used in the operation of the QP-AFM. These developments and applications of MP-SPMs are reviewed in this paper.

Theoretical Analysis of a Dual-Probe Scanning Tunneling Microscope Setup on Graphene

“…To this aim multiprobe STM has been used to characterize a wide range of systems [25], including carbon nanotubes [26], Si-nanowires [27,28], two-dimensional thin films [29], and graphene [28,30,31]. This technique analyzes nanoscale features on surfaces without the need to fabricate invasive contacts into the sample [30][31][32][33].…”

Dual-probe spectroscopic fingerprints of defects in graphene

“…Such setups have been achieved experimentally [23][24][25][26][27][28] and the recent progress is reviewed in detail in Refs. [29,30]. State-of-the-art experimental techniques [24,31] allow for tip separations down to 50-100 nm.…”

Scanning tunneling potentiometry implemented into a multi-tip setup by software

“…[1][2][3][4] The most common experiments reported in the literature using those instruments are multi-probe measurements that allow to determine the microscopic electrical properties of the samples under investigation. However, such devices can be further extended with scanning tunneling potentiometry (STP) techniques which allow to map the electric potential on the nanoscale with spatial and potential resolution of few Å and µV, respectively.…”