41,220 research outputs found
Local Electrical Stress-Induced Doping and Formation of 2D Monolayer Graphene P-N Junction
We demonstrated doping in 2D monolayer graphene via local electrical
stressing. The doping, confirmed by the resistance-voltage transfer
characteristics of the graphene system, is observed to continuously tunable
from N-type to P-type as the electrical stressing level (voltage) increases.
Two major physical mechanisms are proposed to interpret the observed phenomena:
modifications of surface chemistry for N-type doping (at low-level stressing)
and thermally-activated charge transfer from graphene to SiO2 substrate for
P-type doping (at high-level stressing). The formation of P-N junction on 2D
graphene monolayer is demonstrated with complementary doping based on locally
applied electrical stressing.Comment: 12 pages, 4 figure
Parameter estimation and model testing for Markov processes via conditional characteristic functions
Markov processes are used in a wide range of disciplines, including finance.
The transition densities of these processes are often unknown. However, the
conditional characteristic functions are more likely to be available,
especially for L\'{e}vy-driven processes. We propose an empirical likelihood
approach, for both parameter estimation and model specification testing, based
on the conditional characteristic function for processes with either continuous
or discontinuous sample paths. Theoretical properties of the empirical
likelihood estimator for parameters and a smoothed empirical likelihood ratio
test for a parametric specification of the process are provided. Simulations
and empirical case studies are carried out to confirm the effectiveness of the
proposed estimator and test.Comment: Published in at http://dx.doi.org/10.3150/11-BEJ400 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
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