One-volt, solution-processed organic transistors with self-assembled monolayer-Ta2O5 gate dielectrics

Mohammadian N., Faraji S., Sagar S., Das B. C., Turner M. L., Majewski L. A.

Materials, vol.12, no.16, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 12 Issue: 16
  • Publication Date: 2019
  • Doi Number: 10.3390/ma12162563
  • Journal Name: Materials
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Anodization, One-volt operation, Organic thin-film transistor (OTFT), Self-assembled monolayer (SAM) modification, Tantalum oxide
  • Istanbul Technical University Affiliated: No


Low-voltage, solution-processed organic thin-film transistors (OTFTs) have tremendous potential to be key components in low-cost, flexible and large-area electronics. However, for these devices to operate at low voltage, robust and high capacitance gate dielectrics are urgently needed. Herein, the fabrication of OTFTs that operate at 1 V is reported. These devices comprise a solution-processed, self-assembled monolayer (SAM) modified tantalum pentoxide (Ta2O5) as the gate dielectric. The morphology and dielectric properties of the anodized Ta2O5 films with and without n-octadecyltrichlorosilane (OTS) SAM treatment have been studied. The thickness of the Ta2O5 film was optimized by varying the anodization voltage. The results show that organic TFTs gated with OTS-modified tantalum pentoxide anodized at 3 V (d ~7 nm) exhibit the best performance. The devices operate at 1 V with a saturation field-effect mobility larger than 0.2 cm2 V-1 s-1, threshold voltage -0.55 V, subthreshold swing 120 mV/dec, and current on/off ratio in excess of 5 × 103. As a result, the demonstrated OTFTs display a promising performance for applications in low-voltage, portable electronics.