3Spectrofluorimetric measurements, Science 298, 2361 (2002) Cross-section model of a SWCNT in a cylindrical SDS micelleSDS: sodium dodecyl sulfate (SDS) surfactant.
4Spectrofluorimetric measurements, Science 298, 2361 (2002) (A) Contour plot of fluorescence intensity versus excitation and emission wavelengths for a sample of SWNTs suspended in SDS and deuterium oxide.(B) Circles show spectral peak positions from (A); lines show perceived patterns in the data.
8triad structure of zigzag tubes xtriad structure of zigzag tubes1/d(due to trigonal warping)n=3i+1n=3i+2n=3iMKGn mod3 = 0n mod3 = 1n mod3 = 2
9Lines of allowed k vectors for the three nanotube families on a contour plot of the electronic band structure of graphene (K point at center).(a) metallic nanotube belonging to the ν = 0 family(b) semiconducting −1 family tube(c) semiconducting +1 family tubeBelow the allowed lines the optical transition energies Eii are indicated. Note how Eii alternates between the left and the right of the K point in the two semiconducting tubes. The assumed chiral angle is 15◦ for all three tubes; the diameter was taken to be the same, i.e., the allowed lines do not correspond to realistic nanotubes.
10(a) Kataura plot: transition energies of semiconducting (filled symbols) and metallic (open) nanotubes as a function of tube diameter (Calculated from the Van-Hove singularities in the joint density of states within the third-order tight-binding approximation.)(b) Expanded view of the Kataura plot highlighting the systematics in (a) The optical transition energies follow roughly 1/d for semiconducting (black) and metallic nanotubes (grey). The V-shaped curves connect points from selected branches (2n+m = 22, 23 and 24). For each nanotube subband transition Eii it is indicated whether the ν = −1 or the +1 family is below or above the 1/d average trend. Squares (circles) are zigzag (armchair) nanotubes.
11Nanocső lerakása szuszpenzióból forgótárcsás (spin-coating) technikával Cees Dekker, Delft Univ of Tech 13Cees Dekker, Delft Univ of Tech 13
12Figure 16. Quantum-molecular wire—a 1-nanometer-diameter nanotube on a silicon/ silicon dioxide substrate with two metal electrodes—exhibits conductivity in a stepwise fashion. The device is similar to a transistor with the bias voltage applied between the platinum wires, and the gate varying the electrostatic potential of the nanotube. The tiny size of the nanotube permits just a few quantum energy levels for the electrons (above), so that only at a certain gate voltage does the state fit into the bias window, allowing electrons to smoothly tunnel through.