Contact Length Scaling in Staggered Organic Thin-Film Transistors

In this letter, the contact length (source and drain electrodes length) scaling potential in staggered organic thin-film transistors (OTFTs) was studied. We performed the effect of gate-source voltage, channel length, semiconductor film thickness, mobility, material disorder, anisotropy of mobility, and Schottky barrier between organic semiconductor and source/drain electrodes on the contact length downscaling, and found that the contact resistance do not increase until the contact length is scaled down to sub-500 nm. Importantly, the cutoff frequency (f_T) of OTFTs was described and it was found that f_T would increase with the decrease of contact length and the highest f_T could be obtained with contact length in the range of sub-100 nm with Ohmic contacts. This letter showed excellent contact length scaling potential of OTFTs and provided guidelines for the design of high frequency, low-cost, and printable OTFTs.