PVP-SiO2 and PVP-TiO2 hybrid films for dielectric gate applications in CdS-based thin film transistors

M. S. de Urquijo-Ventura, M. G.Syamala Rao*, S. Meraz-Davila, J. A.Torres Ochoa, M. A. Quevedo-Lopez, R. Ramirez-Bon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

We report a simple solution process to deposit organic-inorganic poly (vinyl phenol) (PVP)–SiO2 and PVP-TiO2 hybrid films. The spin dropped hybrid films were prepared at low-temperature and their main properties were studied by TGA, FE-SEM, AFM, FTIR, XPS and contact angle measurements. The results show that the surface of the PVP-SiO2 and PVP-TiO2 hybrid films is smooth with very low surface roughness of 0.25 and 0.51 nm, and surface energy of 48.4 and 40.1 mJ/m2, respectively. The electrical properties of the hybrid films, measured on MIM devices, show low leakage current density under 10−7 A/cm2 and dielectric constant of 5 and 4.6 at 1 kHz, respectively. The hybrid films were used as gate dielectric in solution-processed CdS thin film transistors (TFTs), showing diverse performance. The CdS/PVP-SiO2 devices showed high mobility of 18 cm2/Vs, on/off current ratio of 104, low threshold voltage of 0.6 V and subthreshold swing of 0.25 V/dec. Whereas, the corresponding values for the CdS/PVP-TiO2 ones were 0.45 cm2/Vs, 104, 1.9 V and 1.25 V/dec, respectively. The lower electrical performance of the CdS/PVP-TiO2 devices was attributed to the mismatching surface energies between the surfaces of the dielectric and semiconductor layers, and to the influence of a large number of trapped charges at this interface.

Original languageEnglish
Article number122261
JournalPolymer (United Kingdom)
Volume191
DOIs
StatePublished - 16 Mar 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2020 Elsevier Ltd

Keywords

  • CdS TFTs
  • Hybrid dielectrics
  • Solution process
  • Surface energy

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