Four-probe measurements with a three-probe scanning tunneling microscope

Abstract

We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

Progress and development in multiple-probe scanning probe microscopes

“…而 四探针法通过一次测量便可获得样品本征电学性质, 消除了接触电阻影响, 因此QP-SPM得到迅速发展. Salomons等人 [19] 制 造的TP-STM集 成了 SEM和场离 [25] 设计的QP-STM则是根据球坐标系粗调运动, 可 较容易调节探针与样品的夹角. Higuchi等人 [26] 设计 的QP-STM采用样品扫描的方式不仅可较容易地同 时获得4幅图像, 且能够有效防止撞针事故的发生.…”

“…https://engine.scichina.com/doi/10.1360/N972018-00909 [18] 示意图. (b) TP-STM [19] 的照片. (c) 超紧凑的QP-STM [20] 的照片.…”

“…(a) Schematic diagram of compact DP-STM with multilayer rings [18] . (b) Photo of TP-STM [19] . (c) Photo of ultra compact QP-STM [20] .…”

Invited Review Article: Multi-tip scanning tunneling microscopy: Experimental techniques and data analysis

“…After the first multi-tip STM was introduced, 38 several home-built instruments were designed [39][40][41][42][43][44][45][46] and, today, multiple commercial instruments are available as well. [47][48][49][50] In some cases, commercial instruments have been modified.…”

Upgrade of a commercial four-probe scanning tunneling microscopy system

“…However, initially STM/SPM systems had only one probe, and this single-probe (1-P) configuration limited its application in measuring the lateral electrical conductivity of nanostructures, 17,18 such as nanowires and 2D materials. In order to fully utilize the ultra-high spatial resolution of STM in traditional transport measurements, multi-probe SPM systems have emerged, with double probes, [19][20][21] triple probes, 22,23 or even four probes. [24][25][26][27][28][29][30] Among these, the four-probe (4-P) STM is ideal for combining the ultra-high spatial resolution of STM with standard four probe transport measurements in situ.…”