Ambipolar and anti-ambipolar thin-film transistors from edge-on small-molecule heterostructures

Abstract

Heterostructure electronic devices potentially provide opportunities for novel transistor operations, including ambipolar and anti-ambipolar switching characteristics. However, there are still no previous studies investigating the physical, chemical, and morphological properties of small-molecule semiconductor films deposited as heterojunctions. Here, we systemically investigate chemical and morphological structure in a heterostructure of small-molecule organic semiconductors using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption of fine structure (NEXAFS), and ultraviolet photoelectron spectroscopy (UPS). The analysis reveals that dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) and N,N′-ditridecylperylenediimide (PTCDI-C13) maintain their chemical compositions, energy structure, and edge-on molecular orientations (tilt angle = 66°). Furthermore, ambipolar and anti-ambipolar transistors are demonstrated using the edge-on DNTT/PTCDI-C13 heterostructure. These transistors enable CMOS-like inverter and ternary inverter operations as respective example applications of ambipolar and anti-ambipolar transistors. © 2020 Elsevier B.V.