Transconductance and Coulomb Blockade Properties of In-Plane Grown Carbon Nanotube Field Effect Transistors

Suppression of Blinking and Enhanced Exciton Emission from Individual Carbon Nanotubes

“…Spectral diffusion can be eliminated if local charge fluctuations in the SWCNT environment are removed, which would otherwise lead to local electric-field-induced Stark effects in the PL emission. On the microscopic scale there are several possible mechanisms to account for spectral diffusion or changes to the exciton oscillator strength, such as protonation at the sidewalls of the SWCNTs during local chemical reactions with acids and bases, , modified band gap values caused by oxygen doping upon ozone/light treatment, or removal of surface-bound water molecules proximal to the nanotubes. − Interestingly, we also observe that after about two weeks of exposure to ambient air the PMMA-covered samples degrade and, as a result, again display spectral diffusion and blinking. Subsequent heat treatment again results in strong suppression of spectral diffusion and blinking signatures, demonstrating that the effect is reversible.…”

“…However, since this approach is not compatible with integration of SWCNTs into cavities, we instead capped the samples with 500 nm PMMA (see Figure c) followed by baking on a hot plate at 150 °C for several days in ambient air to remove surface-bound water molecules. Using the same technique, initially introduced by Kim et al ., we have recently demonstrated that gate hysteresis can be fully eliminated in in-plane grown SWCNT field effect transistors …”

“…Using the same technique, initially introduced by Kim et al, 27 we have recently demonstrated that gate hysteresis can be fully eliminated in in-plane grown SWCNT field effect transistors. 30 Figure 2d shows the corresponding spectral trajectory for a PMMA-covered/baked (6,5) SWCNT displaying remarkably less spectral diffusion and blinking. Spectral diffusion can be eliminated if local charge fluctuations in the SWCNT environment are removed, which would otherwise lead to local electric-fieldinduced Stark effects in the PL emission.…”

“…In order to eliminate spectral diffusion, we followed the idea that the photo-created charges cannot tunnel in or out of the SWCNTs if charge trap states are removed from the local environment. As is well-known, CNTs integrated in field-effect transistors suffer from gate hysteresis effects due to local charge trapping by the SiO 2 surface-bound water, which is attached to the silane groups proximal to the nanotubes. − This gate hysteresis effect can be removed by elevating CNTs bridging an air gap, similar to the elimination of spectral diffusion in free-standing CNTs . However, since this approach is not compatible with integration of SWCNTs into cavities, we instead capped the samples with 500 nm PMMA (see Figure c) followed by baking on a hot plate at 150 °C for several days in ambient air to remove surface-bound water molecules.…”

Quantum Mechanics Design of Two Photon Processes Based Solar Cells

“…These have been observed in devices like the single electron transistor (SET) (Aleiner et al, 2002). Coulomb blockade enables very strong control of electron transport through SET channel so that the gate switches from insulating state to conducting with one electron charge accuracy (Ai et al, 2010). Likewise, modified PS that has pore size in the range of several deca-nanometers can behave as a quantum system if the characteristic size of the modifier (here QDs) is comparable with the electron wavelength in that material.…”