Effect of molecular weight of gate dielectric (Polyvinylalcohol) and solvents on operational stability of organic field effect transistors

Author(s): E.Basaran, A.Altýndal, K.Esmer, Z.Alpaslan, D.Malko

The effects ofmolecularweight and the solvents used for gate dielectric deposition on output and transfer characteristics ofOFETdeviceswith bottomgate contact have been studied. Polyvinylalcohol (PVA)withmolecularweights 30000 and 145000 g/ mol (PVA1 and PVA2, respectively)was used as gate dielectric and deionized-water and dimethylsulfoxide (DMSO) as solvents.This studydemonstratedthat both themolecularweight and solvent affect the output and transfer characteristics of theOFETdevices.Consider-ableimprovement inthresholdvoltagehasbeenachieved for eachmolecularweight in the case ofDMSOused as solvent. The observed clockwise hysteresis fromthe Vgs-Ids curves and their solvent dependence implies that the presence of the polar groups inside the gate dielectric can control device characteristics.

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