Scanning Electrochemical Microscope

The CHI900 Scanning Electrochemical Microscope consists of a digital function generator, a bipotentiostat, high resolution data acquisition circuitry, a three dimensional micropositioner, an Inchworm motor controller, and sample and cell holder. The three dimensional micropositioner has a spatial resolution better than one nanometer but it allows a maximum traveling distance of several centimeters. The potential control range of the bipotentiostat is ± 3.275V and the current range is ± 10 mA. The instrument is capable of measuring current down to sub-picoamperes.

In addition to SECM imaging, two other modes of operation are provided for scanning probe applications: the Probe Scan Curve mode and the Probe Approach Curve mode. The Probe Scan Curve mode allows the probe to move in X, Y, or Z direction while the probe and substrate potentials are controlled and currents are measured. The probe can be stopped when the current reaches a specified level. This is particularly useful in searching for an object on the surface and determining approach curves. The Probe Approach Curve mode allows the probe to approach the surface of the substrate. It is also useful in distinguishing the surface process. The PID control is used in this case. It automatically adjusts the step size to allow fast surface approach yet without the probe touching the surface.

The CHI900 is designed for scanning electrochemical microscopy, but many conventional electrochemical techniques are also integrated for convenience, such as CV, LSV, CA, CC, DPV, NPV, i-t, DPA, and TPA. The bipotentistat works for CV, LSV, DPV, and for amperometric i-t curves. In CV, LSV and DPV, the potential of both channels can be scanned simultaneously.

The instrument is controlled by an external PC under a Windows environment. It is easy to install and use. No plug-in card or other hardware is required on the PC side. The user interface follows the Windows application design guide. If users are familiar with Windows application, they can use the software even without an operation manual or on-line help. The commands, parameters, and options use terminology that is familiar to most chemists. The toolbar allows quick access to the most commonly used commands. The help system provides context sensitive help. It is systematic and complete.

CH Instruments, Inc., 676 Germantown Pkwy., Suite 517, Cordova, TN 38018. Tel: 901-754-2688. Fax: 901-751-0394.