The custom-built setup is capable of electrical transport measurements in the following conditions:
- Vacuum (down to 10-5 mbar pressure)
- Controlled relative humidity (0 to 80%)
- Controlled gas environment
- Temperature ranging from 300 K to 400 K
- Magnetic field range of ±25 mT
- AC electrical excitation (up to 100 kHz)
The electrical transport measurements are automated and can be performed continuously in a fixed or varying environment. Further customisation is possible upon request, such as 2-wire device measurements, DC excitation and mixed gas environments.
Measurement chamber (top). Sample holder probing a continuous conductive film (bottom – left) and a microscale device on a chip (bottom – right). The electrical contacts of the microscale device are extended to a chip carrier via wire bonding.
Representative results from a CVD grown graphene film on SiO2 (left) and a water-based conductive ink printed on a glass substrate (right). The environment changes from vacuum to air for the graphene sample (left). The response in the electrical properties is very clear: the sheet resistance drops and the majority carrier type switches from electrons to holes. For the printed ink device, the relative humidity is varied between 80% and 10% (right). Orders of magnitude change in the sheet resistance is captured as a result.