Impact of surface roughness on conduction in molecular semiconductors

Abstract

The interface roughness between gate insulator and semiconductor is expected to reduce the conductance of molecular field-effect transistors. This study merges atomic force microscopy data of layer topographies with self-consistent calculations of charge carrier densities and conductances within the channel region. It is found that a roughness equivalent to one monolayer reduces the conductance by nearly 50%. Currents flow mainly within the first monolayer of the semiconductor and along percolation pathways, where charges rarely undergo transfers between adjacent monolayers.