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Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots

O. Makarovsky ; L. Turyanska ; N. Mori ; M. Greenaway ; L. Eaves ; A. Patane ; M. Fromhold ; Samuel Lara-Avila (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; Sergey Kubatkin (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; R. Yakimova
2d Materials (2053-1583). Vol. 4 (2017), 3,
[Artikel, refereegranskad vetenskaplig]

We report a simultaneous increase of carrier concentration, mobility and photoresponsivity when SiC-grown graphene is decorated with a surface layer of colloidal PbS quantum dots, which act as electron donors. The charge on the ionised dots is spatially correlated with defect charges on the SiC-graphene interface, thus enhancing both electron carrier density and mobility. This charge-correlation model is supported by Monte Carlo simulations of electron transport and used to explain the unexpected 3-fold increase of mobility with increasing electron density. The enhanced carrier concentration and mobility give rise to Shubnikov-de Haas oscillations in the magnetoresistance, which provide an estimate of the electron cyclotron mass in graphene at high densities and Fermi energies up to 1.2 x 10(13) cm(-2) and 400 meV, respectively.

Nyckelord: SiC-graphene, unipolar charge correlation, colloidal quantum dots, Monte Carlo simulations

Denna post skapades 2017-07-20.
CPL Pubid: 250749


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Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik



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