NPL has electrical measurements services capable of characterising the electrical transport properties: the electrical resistivity (or conductivity), majority carrier type (electrons or holes), charge carrier density and mobility. These measurements can be done in a wide range of conditions:
NPL’s capabilities enable the development and optimisation of new devices to be accelerated, including for environmentally-sensitive applications.
The custom-built setup is capable of electrical transport measurements in the following conditions:
Ambient
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.
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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. |
Temperature ranging from 2 K to 400 K
Magnetic field range of ±9 T
Custom electrical measurements are available by integrating external measurement equipment with PPMS, such as transistor measurements, 2-wire device measurements.
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PPMS (left) and its sample holder with a graphene FETs chip (top – right) and a thin film on SiO2/Si substrate (bottom – right)
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Representative PPMS results: Temperature-dependent mobility for 3 different materials: a graphene Hall bar device (top), a composite film (middle), conductive ink printed on a glass substrate (bottom). |
Capability |
ETMiVE |
PPMS |
Temperature range |
300 K to 400 K | 2 K to 400 K |
Conditions |
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Electrical excitation |
AC (up to 100 kHz) | DC, AC (up to 200 Hz) |
Magnetic field |
±25 mT | ±9 T |
Simultaneous measurements |
1 | 2 for AC, 3 for DC |
Sample dimensions |
< 1 cm | < 1 cm |
Sample type |
van der Pauw | van der Pauw Hall bar |
Upper R limit |
0.1 MΩ | 1 MΩ |
Lower mobility limit |
10 cm2 V-1 s-1 | < 1 cm2 V-1 s-1 |
For van der Pauw measurements:
The service could support the following applications and sectors:
Our research and measurement solutions support innovation and product development. We work with companies to deliver business advantage and commercial success.
Contact our Customer Services team on +44 20 8943 7070
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