Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots
Journal article, 2017
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.
unipolar charge correlation
Monte Carlo simulations
SiC-graphene
colloidal quantum dots
Author
O. Makarovsky
University of Nottingham
L. Turyanska
University of Lincoln
University of Nottingham
N. Mori
Osaka University
M. Greenaway
University of Nottingham
Loughborough University
L. Eaves
University of Nottingham
A. Patane
University of Nottingham
M. Fromhold
University of Nottingham
Samuel Lara Avila
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Sergey Kubatkin
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
R. Yakimova
Linköping University
2D Materials
2053-1583 (eISSN)
Vol. 4 3 031001Subject Categories
Physical Sciences
Nano Technology
Condensed Matter Physics
DOI
10.1088/2053-1583/aa76bb