P-4: Synthesis and Applications of PVP-TiO[sub 2] Composite as a Gate Insulator for Organic Thin-Film Transistors

Abstract

High dielectric constant of gate insulators is one of the essential factors for reducing the threshold voltage of OTFTs. Viewed in this light, PVP solution mixed with high-k TiO 2 was synthesized and utilized as a gate insulator for lowering the threshold voltage and enhancing the subthreshold swing of OTFTs. As a result, we could increase the dielectric constant of the PVP-based insulator up to 5.8, and the OTFTs with the composite insulator showed the threshold voltage of about -8.3 V and the subthreshold slope of about 1.5 V/decade, which are the optimized properties compared to those of OTFTs with PVP in this study.

Characteristic of Organic Thin Film Transistor with a High-k Insulator of Nano-TiO2 and Polyimide Blend

“…It indicates that a strong correlation between the morphology and the leakage current density of gate dielectric film is reflected in the OTFT device performance. Compared with those shown in previous studies on nanocomposite gate dielectric, 10) the on-off ratio of the pentacene OTFT device deposited on the nanocomposite gate dielectric is always much worse than that deposited on the neat polymer gate dielectric. However, in our work, because nano-TiO 2 particles were dispersed well in PI to form a homogeneous nanocomposite film, the leakage current density of the nanocomposite is comparable to that of the neat PI, resulting in a high on-off ratio (>10 5 ) of the OTFT device.…”

Study on Preparation of High-k Organic–Inorganic Thin Film for Organic–Inorganic Thin Film Transistor Gate Dielectric Application

“…However, even at a high content of TiO 2 (5 vol %), because TiO 2 nanoparticles whose surfaces were further modified with 2 wt % dispersant were well dispersed in the polyimide slurry in this study, the surface roughness of the gate dielectric film is still small (2.3 nm) compared with those shown in previous nanocomposite studies. 13) To confirm the homogeneity of the nanocomposite gate dielectric film, five positions (one center, four corners) for the nanocomposite dielectrics with 1 and 2 vol % TiO 2 contents were examined by AFM and are shown in Figs. 8 and 9, respectively.…”

Solution‐processed organic TFT array for active‐matrix LCDs on a plastic substrate

“…In order to fabricate an OTFT with higher mobility, it is important to control the surface energy of the gate insulator layer. Thus far, the surface energy has been modified by introducing a novel organic insulator 9,10 or surface treatment with a silane coupling agent (SCA). [11][12][13][14][15][16] Synthesis of a new material is, however, generally difficult and the reproducibility of the surface-treatment process with the SCA is quite sensitive to the process conditions and environment.…”