Pentacene field-effect transistors with sub-10-nm channel lengths

The field effect in pentacene thin-film transistors was studied using bottom-contact devices with channel lengths below $10\mathrm{nm}$ . To suppress spreading current in these devices, which have a small channel width-to-length (W-L) ratio, we employed a pair of guarding electrodes as close as $20\mathrm{nm}$ to the two sides of the channel. The responses of these nanometer scale transistors exhibit good gate modulation. Mobilities of $0.046{\mathrm{cm}}^2∕\mathrm{Vs}$ and on/off ratios of 97 were achieved in sub-$10\text{-}\mathrm{nm}$ transistors. We find that the device response is strongly influenced by the nature of the metal-semiconductor contact.