Bottom-contact small-molecule n-type organic field effect transistors achieved via simultaneous modification of electrode and dielectric surfaces

Low-voltage, n-type organic field effect transistors (OFETs) with simultaneously modified bottom-contact (BC) electrodes and dielectric were compared to their top-contact (TC) counterparts. The devices modified with 6-phenoxyhexylphosphonic acid (Ph6PA) self-assembled monolayer (SAM) showed similar performance, morphology, and contact resistance. Electron mobility of C-60 devices were 0.212 and 0.320 cm(2) V-1 s(-1) and [6,6]-phenyl-C-61-butyric acid methyl ester (PCBM) devices were 0.04 and 0.06 cm(2) V-1 s(-1) for TC and BC devices, respectively. Low contact resistance between 11 and 45 k Omega cm was found regardless of device architecture or n-type semiconductor used. This work shows it is possible to fabricate solution processable low-voltage bottom-contact devices with performance that is similar or better than their top-contact counterparts without the addition of complex and time-consuming processing steps. (C) 2012 Elsevier B.V. All rights reserved.