  Cyclotron resonance of a Landau-quantized graphene can absorb significant
amount of infrared light. However, application of this phenomenon to the
photodetector had been limited due to the lack of efficient photon to charge
conversion scheme. Here, we demonstrate the detection of cyclotron resonance in
a partially metal-masked monolayer graphene two-terminal device using
photo-Nernst effect. Due to the presence of the mask, incident infrared light
is irradiated on only one-half of the graphene channel. This partial
irradiation creates a temperature gradient perpendicular to the graphene
channel. In the presence of an external magnetic field, thermopower is
generated perpendicular to the temperature gradient due to the Nernst effect.
Consequently, photo-Nernst voltage is generated along the graphene channel,
which can be detected from the contacts on both ends of the channel. We
demonstrate selective detection of the photo-Nernst effect while minimizing the
other photovoltaic contributions, such as the photo-Seebeck effect. We
investigate the dependence of the photo-Nernst effect on magnetic field and
excitation wavelength, which reveals a significant enhancement of photo-Nernst
signal at the cyclotron resonance conditions in graphene. Our finding could
facilitate the realization of far-infrared light detector using cyclotron
resonance of graphene.
