EGaIn: Software to control and measure molecular junctions

This is the software we use in our lab to measure the J/V properties of molecular junctions. It supports serial communication with a Keithley Model 6430 Sub-Femtoamp Remote SourceMeter. We use an RS-232 to USB adapter. Data are written to text files formatted for ingestion by our GaussFit software.

The "EGaIn setup" consists of a syringe full of eutectic Ga-In suspended over a substrate. Tips and junctions can be formed manually or through software by entering the IP address of a Newport ESP302 3-Axis controller that is connected to the measurement stage. thermoelectric measurements can be performed using an Arduino device flashed with the peltier.ino file. The Arduino uses Adafruit MAX31855 thermocouples to measure temperature and a standard 12 V peltier plate to apply thermal gradients. Temperature control is achieved with a MOSFET on the negative terminal and the direction by two DPDT switches, all controlled by pins on the Arduino. We will eventually include schematics as well.

Important

This software uses RS-232, not GPIB. Follow these steps to set the electrometer to RS-232 mode:

1. Press MENU
2. Navigate to COMMUNICATION and then press ENTER
3. Select RS-232 and press ENTER (the electrometer needs to reboot for this setting to take effect)