Dry growth of n-octylphosphonic acid monolayer for low-voltage organic thin-film transistors
Gupta, Swati and Gleskova, Helena (2013) Dry growth of n-octylphosphonic acid monolayer for low-voltage organic thin-film transistors. Organic Electronics, 14 (1). pp. 354-361. ISSN 1566-1199 (https://doi.org/10.1016/j.orgel.2012.10.016)
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Abstract
Dry method for monolayer deposition of n-octylphosphonic acid (C8PA) on the surface of aluminium oxide (AlOx) is presented. Vacuum thermal evaporation is employed to deposit initial thickness corresponding to several C8PA monolayers, followed by a thermal desorption of the physisorbed C8PA molecules. AlOx functionalized with such C8PA monolayer exhibits leakage current density of ∼10−7 A/cm2 at 3 V, electric breakdown field of ∼6 MV/cm, and a root-mean-square surface roughness of 0.36 nm. The performance of low-voltage pentacene thin-film transistors that implement this dry AlOx/C8PA gate dielectric depends on C8PA desorption time. When the desorption time rises from 25 to 210 min, the field-effect mobility increases from ∼0.02 to ∼0.04 cm2/V s, threshold voltage rises from ∼−1.2 to ∼−1.4 V, sub-threshold slope decreases from ∼120 to ∼80 mV/decade, off-current decreases from ∼5 × 10−12 to ∼1 × 10−12 A, on/off current ratio rises from ∼3.8 × 104 to ∼2.5 × 105, and the transistor hysteresis decreases from 61 to 26 mV. These results collectively support a two stage model of the desorption process where the removal of the physisorbed C8PA molecules is followed by the annealing of the defect sites in the remaining C8PA monolayer.
ORCID iDs
Gupta, Swati and Gleskova, Helena ORCID: https://orcid.org/0000-0001-7195-9639;-
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Item type: Article ID code: 42449 Dates: DateEventJanuary 2013Published9 November 2012Published OnlineSubjects: Technology > Electrical engineering. Electronics Nuclear engineering Department: Faculty of Engineering > Electronic and Electrical Engineering Depositing user: Pure Administrator Date deposited: 03 Jan 2013 15:05 Last modified: 18 Oct 2024 22:35 URI: https://strathprints.strath.ac.uk/id/eprint/42449