In situ vacuum measurement of the thickness dependence of electron mobility in naphthalenetetracarboxylic diimide-based field-effect transistors

Abstract

We present an in situ electrical measurement for the characteristics of n-channel organic field-effect transistors (OFETs) based on N,N′-dipentadecafluorooctyl-1,4,5,8-naphtalene tetracarboxylic diimide (NTCDI-C8F15) organic semiconductors. The field-effect mobilities have been estimated as a function of the number of monolayers (MLs). The electron mobility (μe) of NTCDI-C8F15 OFET as thin as 2 ML has been determined. μe increases rapidly with increasing film thickness, although it reaches saturation thickness (d0) around 3.5 ML. Atomic force microscopy confirms island mode growth mechanism of NTCDI-C8F15 with near upright position stacking on SiO2 substrate and it is attributed to the fluorophobic effect of the material.