Wada Y, Enokida I, Yamamoto J, Furukawa Y. Raman imaging of carrier distribution in the channel of an ionic liquid-gated transistor fabricated with regioregular poly(3-hexylthiophene).
Spectrochim Acta A Mol Biomol Spectrosc 2018;
197:166-169. [PMID:
29398591 DOI:
10.1016/j.saa.2018.01.043]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/07/2018] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
Raman images of carriers (positive polarons) at the channel of an ionic liquid-gated transistor (ILGT) fabricated with regioregular poly(3-hexylthiophene) (P3HT) have been measured with excitation at 785 nm. The observed spectra indicate that carriers generated are positive polarons. The intensities of the 1415 cm-1 band attributed to polarons in the P3HT channel were plotted as Raman images; they showed the carrier density distribution. When the source-drain voltage VD is lower than the source-gate voltage VG (linear region), the carrier density was uniform. When VD is nearly equal to VG (saturation region), a negative carrier density gradient from the source electrode towards the drain electrode was observed. This carrier density distribution is associated with the observed current-voltage characteristics, which is not consistent with the "pinch-off" theory of inorganic semiconductor transistors.
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