Enhanced photosensitivity of electro-oxidized epitaxial graphene

Mikhail E. Itkis (1) , Feihu Wang (1) , Palanisamy Ramesh (1) , Elena Bekyarova (1) , Sandip Niyogi (1) , Xiaoliu Chi (1) , Claire Berger (2) , Walt A. de Heer (3) , Robert C. Haddon (1)

1 Center for Nanoscale Science and Engineering [Riverside]
2 NEEL - QuantECA - Circuits électroniques quantiques Alpes
3 School of Physics

We report the enhanced photosensitivity of epitaxial graphene (EG) after electrochemical oxidation in nitric acid. The onset of photoconductivity appears at a photon energy of ~1.7 eV while the responsivity reaches 2.5 A/W at a wavelength of 470 nm (blue light, energy 2.64 eV) and further increases to 200 A/W in the UV spectral range (3.5 eV, 350 nm). The observed photoresponse is attributed to the formation of deep traps at the electro-oxidized EG interface, which release charge carriers under illumination and prolong the life time of the photocarriers. Potential applications of electro-oxidized EG in ultraviolet photodetection are discussed

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Mikhail E. Itkis, Feihu Wang, Palanisamy Ramesh, Elena Bekyarova, Sandip Niyogi, et al.. Enhanced photosensitivity of electro-oxidized epitaxial graphene. Applied Physics Letters, 2011, 98 (9), pp.093115. ⟨10.1063/1.3562316⟩. ⟨hal-01002904⟩