Field-dependent charge transport in organic thin-film transistors: Impact of device structure and organic semiconductor microstructure

Organic semiconductors are highly susceptible to defect formation, leading to electronic states in the gap—traps—which typically reduce the performance and stability of devices. To study these effects, we tuned the degree of charge trapping in organic thin-film transistors by modifying the film depo...

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Veröffentlicht in:Applied physics letters 2019-08, Vol.115 (7)
Hauptverfasser: Anand, Sajant, Goetz, Katelyn P., Lamport, Zachary A., Zeidell, Andrew M., Jurchescu, Oana D.
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Sprache:eng
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Zusammenfassung:Organic semiconductors are highly susceptible to defect formation, leading to electronic states in the gap—traps—which typically reduce the performance and stability of devices. To study these effects, we tuned the degree of charge trapping in organic thin-film transistors by modifying the film deposition procedures and device structure. The resulting charge carrier mobility varied between 10−3 and 10 cm2/V s in 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene. We analyzed the data using a Poole-Frenkel-like model and found a strong dependence of mobility on the field in low-mobility transistors and a field-independent mobility in high-performance devices. We confirmed the presence of traps in all films investigated in this study and concluded that the Poole-Frenkel model is not sufficiently sensitive to identify traps when their concentration is below the detection limit.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.5099388