Electrochemical Scanning Tunneling Microscope And Its Applied Research

Scanning Tunneling Microscopy(STM)possesses some functional characteristics,such as atomic resolution,atomic handling and micro-nano fabrication.STM plays an important role in surface science,materials science,life science and other areas of the nanotechnology.Because of the nanotechnology is the technology that using individual atoms and molecules to make things.It studies the properties and application of the material whose structure size within the scope of 0.1 to 100 nm,so the STM is the core tools of nanotechnology research.There are a lot of commercial and homemade STM,and the technology already quite mature,but as the deepening of the research,the material characterization techniques in liquid environment and extreme conditions is arousing people’s attention gradually and most systems used imported materials,the cost is relatively high,so the aim of this article is to build a complete set of STM system with high stability,high precision and can be used in liquid environment within the budget cost.So in this paper,the main work are as follows:(1)According to the piezoelectric effect and the existing structure of various classical piezoelectric nanopositioners,We design and set up a new high stable STM system.It uses the brand new lens body structure,we abandon the piezoelectric tubes used in previous experiments.Instead of it,piezoelectric stacks are used as the component of the nanopositioner.We debug and test its actual features and make a theoretical analysis of the experimental results.(2)We design and manufactur a preamplifier with high magnification.The preamplifier can amplify the tunnel current signal into macro signal,and it also can increase the magnification of the circuit so that the controller can identify and recode data more easily in a certain degree.(3)Based on the programming system of Labview,we build a set of controlsoftware for electrochemical STM,including electrochemical control,scanning control,fast data acquisition,data storage and data processing,etc.The scanning speed of the control software increase nearly 10 times.The improvement of the scan mode of the traditional potentiostat,makes it possible to timely adjust the stretch of the scanning tube and maintain constant height on samples for the tip during when there is a drift between the tip and samples,which would reduces the hysteresis caused by manually adjusting the distance between the tip and sample.And we build a control module for the constant current scanning based on the PID feedback adjustment principle.We also set a processing module for the following image processing.(4)We use the STM system to study the self-assembly of the molecules on solid surface.We use the Scanning tunneling microscope to study the adsorption and decomposition process of water molecules on the surface of Cu(110)with oxygen atoms.