Analysis of the Advantages of Nanostripe-Channel Geometries for Thin-Film Transistors

We analyze the operation of thin-film transistor (TFT) devices where the active semiconductor is patterned into nanostripes (NSs). It is shown that using relatively large separations between stripes can improve current drive capability by more than a factor of 13 for many of the important material families of disordered and solution-processable TFTs. When comparing NS TFTs to unpatterned TFTs under the same operating conditions, NS devices show enhancements in peak carrier density and conductivity along the edges of the stripe. In addition to increasing the drive current, these carrier density enhancements are large enough to potentially lower the contact resistance. Short-channel effects are also greatly reduced, allowing the possibility of scaling down channel lengths for improved operation at high frequencies. This architecture will work especially well for TFT materials in which the mobility increases with carrier density, a common feature in many organic, polymer, and amorphous metal oxide semiconductors. The results of our analysis on NS TFTs not only make TFTs considerably more attractive for existing optoelectronic applications but NS patterning may also provide TFTs an opportunity to expand into new higher frequency and higher performance applications.