Graphene: a Novel Material for Electronics and Optoelectronics

Professor Michael Fuhrer

School of Physics, Monash University, Melbourne

3:30 pm Friday, 2 May 2014, EN515 Lecture Theatre (EN Building), Hawthorn.

Graphene, an atom-thick plane of carbon, is of interest for its unique electronic structure: electrons in graphene obey the Dirac equation for massless particles, complete with a two-component spinor degree of freedom that mimics the spin of a relativistic particle. I will give an introduction to graphene’s unique electronic structure, then follow with two recent examples from my research group which illustrate graphene’s potential for novel applications. First, gapless graphene allows photoabsorption across a wide spectral range, which we exploit to realize an extremely broadband detector. We accomplish ultrafast, sensitive detection via the hot electron photothermoelectric effect at room temperature. We demonstrate room-temperature detection of THz radiation with sensitivity >700 V/W and noise equivalent power of <20 pW/Hz^1/2, competitive with the best commercial room temperature THz detectors. However our device is orders of magnitude faster, with characteristic timescales <100 ps. Second, we measure the electrical conductivity and optical transmission spectra of ultrathin graphite during lithium intercalation. The high doping upon lithium intercalation increases the conductivity to near the phonon-limited value at room-temperature, and also increases the transmission in the visible range, due to Pauli blocking of optical transitions. Transmission as high as 91.7% for sheet resistance of 3.0 Ω is achieved for 19 layer LiC₆, better performance than any other continuous-film electrode.

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