TY - JOUR
T1 - Tuning of electronic properties of nanographene ribbons by a spatially modulated electric field
AU - Chen, S. C.
AU - Chang, C. P.
AU - Lee, C. H.
AU - Lin, M. F.
N1 - Funding Information:
This work was supported by the National Science Council of Taiwan, under the Grant No. NSC 98-2112-M-006-013-MY4. FIG. 1. Geometric structures of (a) an armchair and (b) zigzag ribbon. FIG. 2. Band structures of the N y = 400 [(a)-(c)] and the N y = 401 (d) armchair ribbons under spatially modulated electric fields. λ , d , and V represent the periodic length, the phase shift, and the strength of the modulated electric field, respectively. The Fermi level is set to zero. FIG. 3. The band structure of the N y = 250 zigzag ribbon in the presence of a modulated electric field. FIG. 4. The carrier densities of J = 1 – 3 energy bands of the N y = 400 armchair ribbon at k x = 0 with or without a modulated electric field. FIG. 5. The carrier densities of the partial flat band of the N y = 250 zigzag ribbon at k x = 0.7 and k x = 1 with or without a modulated electric field. FIG. 6. The DOS of the N y = 400 and the N y = 401 armchair ribbons in a modulated electric fields. FIG. 7. DOS of the zigzag ribbon under modulated electric fields. FIG. 8. The V -dependent energy gap is shown for the N y = 400 armchair ribbon [(a)-(b)] and the N y = 250 zigzag ribbon (c) at different λ and different d . The inset in (b) shows the dependence of the energy gap on d at V = 0.045 γ 0 and λ = 1 .
PY - 2010/4/15
Y1 - 2010/4/15
N2 - The electronic properties of a nanographene ribbon can be significantly tuned by a spatially modulated electric field. The modulated electric potential results in the changes of the electronic properties, i.e., modified energy dispersions, creation of extra band-edge states, alteration of the energy gap, and induction of semiconductor-metal transition. The number of the free carrier increases with the increment of the field strength. Through further classification of the carbon atoms, the features of the wave functions are clearly presented, and the carrier distribution is drastically modulated under the influence of the electric field. The periodic length and the phase shift of the modulated electric field induce a change in the y -axis symmetry of the ribbon and have a significant influence on the energy of the partial flat bands, the energy gap and the carrier distribution. The characteristics of the band structure are directly revealed in the density of states (DOS). The number, heights, positions, and spacings of the peaks in DOS are significantly changed. At the Fermi level, DOS is considerably enhanced; that is, more free carriers are created. The predicted results can be verified by optical and transport experiments.
AB - The electronic properties of a nanographene ribbon can be significantly tuned by a spatially modulated electric field. The modulated electric potential results in the changes of the electronic properties, i.e., modified energy dispersions, creation of extra band-edge states, alteration of the energy gap, and induction of semiconductor-metal transition. The number of the free carrier increases with the increment of the field strength. Through further classification of the carbon atoms, the features of the wave functions are clearly presented, and the carrier distribution is drastically modulated under the influence of the electric field. The periodic length and the phase shift of the modulated electric field induce a change in the y -axis symmetry of the ribbon and have a significant influence on the energy of the partial flat bands, the energy gap and the carrier distribution. The characteristics of the band structure are directly revealed in the density of states (DOS). The number, heights, positions, and spacings of the peaks in DOS are significantly changed. At the Fermi level, DOS is considerably enhanced; that is, more free carriers are created. The predicted results can be verified by optical and transport experiments.
UR - http://www.scopus.com/inward/record.url?scp=77952399658&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77952399658&partnerID=8YFLogxK
U2 - 10.1063/1.3372761
DO - 10.1063/1.3372761
M3 - Article
AN - SCOPUS:77952399658
VL - 107
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 8
M1 - 083712
ER -