A new method to invert top-gate organic field-effect transistors for Kelvin probe investigations

Development of an improved Kelvin probe force microscope for accurate local potential measurements on biased electronic devices

“…As the electrical potential distribution is of particular interest for applications such as organic solar cells and organic field effect transistors (OFETs) (Palermo et al, 2006), KPFM-AM has also been extensively applied to characterise organic semiconductor-based devices (Bürgi et al, 2002;Nichols et al, 2003;Puntambekar et al, 2003;Bürgi et al, 2004;Tal et al, 2005) in order to investigate transport mechanisms and injection issues in OFETs. As the bottom-contact structure is suited for potential measurements related to the channel charge distribution, KPFM-AM imaging has been performed on various types of organic thin film devices based on pentacene (Hallam et al, 2009;Nakamura et al, 2009;Yogev et al, 2010;Yogev et al, 2011;Li et al, 2012a,b;Celle et al, 2014;Wu et al, 2014;Yogev & Rosenwaks, 2014), poly(3-hexylthiophene) (P3HT) (Bürgi et al, 2003;Liscio et al, 2012;Kehrer et al, 2013;Musumeci et al, 2014), perylene (Luttich et al, 2012) or oligothiopene (Afsharimani & Nysten, 2012). KPFM also facilitates the characterisation of the carrier injection process at electrode/organic semiconductor interfaces by measuring an injection potential drop (Bürgi et al, 2003;Simonetti et al, 2010).…”