Electronic properties of annealed pentacene films in air at various temperatures up to 400 K

This study examined the electronic properties of annealed pentacene films in air at various temperatures up to 400 K for 1 min. The carrier mobility in pentacene samples exhibits unexpectedly strong temperature dependence, implying the domination of tunneling (hopping) at low (high) temperatures. Upon annealing temperature, the molecule structure is not affected. The room-temperature mobility was drastically increased from 2.42 to 4.73 cm2/V-s by thermal annealing at 350 K. Hall-effect analysis by using the polaron theory revealed that the enhanced mobility by proper annealing is due to the increased spacing between molecules.