Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 40: II-VI semiconductors
HL 40.2: Vortrag
Donnerstag, 15. März 2018, 11:15–11:30, EW 201
DFT assisted tailoring of fluorine-containing molecules for passivation of zinc oxide layers in thin film transistors — •Jonas Köhling1, Nataliya Kalinovich2, Gerd-Volker Röschenthaler2, and Veit Wagner1 — 1Department of Physics & Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany — 2Department of Life Sciences & Chemistry, Jacobs University Bremen, 28759 Bremen, Germany
In this work thin film transistors were fabricated by depositing ZnO thin films with a thickness of 12 nm by spray pyrolysis on substrates with predefined electrodes. Because of their instability against oxygen and moisture the thin film transistors were passivated using for this purpose tailor made β-diketones with trifluormethyl and benzene-derivatives as substituents. These molecules were characterized by DFT calculations in order to correlate their properties to electrical results. After passivation of the ZnO surface transistors exhibit reduced hysteresis, increased mobility and better stability against electrical bias stress. The improvement of ZnO thin film transistors depends on the used passivation molecule. UV-Vis, AFM, XPS and IV measurements were used to characterize optical, morphological and electrical properties, respectively. We conclude that functionalized β-diketones passivate surface traps on solution processed ZnO thin films achieving better stability against oxygen and moisture under electrical operation. Best electrical performance is found for thin film transistors passivated with molecules containing toluene and chlorobenzene side groups.