Graphene, because of its super-thin yet durable and ductile structure, lends itself to possible use in many new applications, including next-generation sensor designs. The most recent Journal of Materials Chemistry C includes a paper on the study of flexible graphene-based materials intended for gas sensors of the future. In the paper (available for download by subscribers), researchers specifically examine how the sensor’s chemical sensitivity is affected by adding hole-accumulating palladium (Pd) and hole-depleting aluminum (Al) nanoparticles to the graphene. For related Hall effect measurements, they relied on a Lake Shore Model 8404 Hall effect measurement system (HMS), obtaining Hall mobility, carrier density and type using the Van der Pauw technique and 610 G reversible magnetic fields.
The Model 8404 HMS, as well as our new Model 8407 HMS, is well-suited for Hall measurements of graphene materials, whether at room temperature (like the gas sensor application above) or over variable temperatures. Because graphene features very high carrier mobility, measuring it can be done with the standard 8400 Series DC field Hall system; an AC field option can added to the 8400 systems for measuring low-mobility materials, such as oxides and organic semiconductors.
Beyond the 8400 Series HMS solutions, Lake Shore also offers other systems for graphene-related research, including:
|Lake Shore system||What it’s ideal for||Application notes|
|Model 9709A HMS||Performing quantum Hall graphene measurements at very low temperature.||It has a powerful 9 T superconducting magnet for high field, so you can distinguish quantum well structures. Multi-quantum wells, such as those found in graphene microribbons, can be characterized, and the system supports quantum Hall effect measurements to 2 K.|
|Model 8501 THz||Characterizing the dynamic conductivity in research-scale graphene samples over a range of temperatures and magnetic fields.||Unaltered by the effects of electrical contacts, continuous wave (CW) THz spectroscopy is used to study the intrinsic carrier dynamics in graphene films. Flat, polished substrates can develop strong Fabry-Perot interference patterns at THz frequencies – effectively acting as a cavity which enhances the optical and magneto-optical response of a graphene overlayer.|
|Model CRX-4K probe station with high vacuum option||Desorbing surface contamination prior to electronically probing graphene devices.||Graphene has electronic properties that can be significantly affected by surface contamination. By heating the sample stage while cooling the surrounding radiation shields, atmospheric surface adsorbates on graphene can be reduced.|
For help choosing a system for your specific research application, please contact us.