Organic/Inorganic Nano-hybrids with High Dielectric Constant for Organic Thin Film Transistor Applications

Abstract

The organic material soluble polyimide (PI) and organic–inorganic hybrid PI–barium titanate (BaTiO3) nanoparticle dielectric materials (IBX, where X is the concentration of BaTiO3 nanoparticles in a PI matrix) were successfully synthesized through a sol–gel process. The effects of various BaTiO3 contents on the hybrid film performance and performance optimization were investigated. Furthermore, pentacene-based organic thin film transistors (OTFTs) with PI-BaTiO3/polymethylmethacrylate or cyclic olefin copolymer (COC)-modified gate dielectrics were fabricated and examined. The hybrid materials showed effective dispersion of BaTiO3 nanoparticles in the PI matrix and favorable thermal properties. X-ray diffraction patterns revealed that the BaTiO3 nanoparticles had a perovskite structure. The hybrid films exhibited high formability and planarity. The IBX hybrid dielectric films exhibited tunable insulating properties such as the dielectric constant value and capacitance in ranges of 4.0–8.6 and 9.2–17.5 nF cm−2, respectively. Adding the modified layer caused the decrease of dielectric constant values and capacitances. The modified dielectric layer without cross-linking displayed a hydrophobic surface. The electrical characteristics of the pentacene-based OTFTs were enhanced after the surface modification. The optimal condition for the dielectric layer was 10 wt% hybrid film with the COC-modified layer; moreover, the device exhibited a threshold voltage of 0.12 V, field-effect mobility of 4.32 × 10−1 cm2 V−1 s−1, and on/off current of 8.4 × 107.

Novel Vapor-Phase Synthesis of Flexible, Homogeneous Organic–Inorganic Hybrid Gate Dielectric with sub 5 nm Equivalent Oxide Thickness

“…Unlike the solution-based polymeric or organic–inorganic hybrid films, − ultrathin film with a physical thickness below 20 nm has been deposited reliably with a precise thickness control while excellent dielectric performance was maintained via the iCVD process. − C i – f (left), C i – E (middle), and J – E (right) characteristics of the hybrid dielectrics (Al concentration: 17.8%) with various thickness were shown in Figure c using MIM devices. The physical thickness of hybrid films was reduced to less than 20 nm without degradation of the insulating properties, resulting in a high C i of 250 nF/cm 2 and low J value below than 1 × 10 –7 A/cm 2 .…”

“…In previous studies, an organic–inorganic dielectric was generated simply by physically mixing inorganic particles into the polymer matrix via a solution process. Aside from the EOT scalability and flexibility, achieving a uniform dispersion of inorganic particles within the polymer matrix and smoothing the surface roughness are additional challenges for the solution process. , Other research efforts have proposed a method of making the organic–inorganic dielectric via solution process using organic monomers and inorganic precursors. , Although hybrid dielectrics with enhanced k values and mechanical flexibility have been demonstrated, it is still challenging to form an ultrathin dielectric that is thinner than a few tens of nanometers for EOT scaling without losing its dielectric performance. , In most cases, a relatively high dielectric thickness, mostly greater than 200 nm, is inevitable for the solution process to minimize the effect of defects such as pinholes and residual impurities stemming from the solution process. Therefore, it is highly desirable to develop ultrathin but high- k organic–inorganic hybrid dielectrics capable of improving the performance of flexible electronic devices.…”

“…Aside from the EOT scalability and flexibility, achieving a uniform dispersion of inorganic particles within the polymer matrix and smoothing the surface roughness are additional challenges for the solution process. 11,12 Other research efforts have proposed a method of making the organic−inorganic dielectric via solution process using organic monomers and inorganic precursors. 13,14 Although hybrid dielectrics with enhanced k values and mechanical flexibility have been demonstrated, it is still challenging to form an ultrathin dielectric that is thinner than a few tens of nanometers for EOT scaling without losing its dielectric performance.…”

Dielectric Properties of ZnO-Based Nanocomposites and Their Potential Applications

“…e performance of a TFT is greatly influenced by the properties of its dielectric layer. e dielectric layer is responsible for the accumulation of charge in the channel and leakage current in the device [52,53]. ere is a fundamental limitation on the thickness of a silicon-based gate dielectric that the oxides having a thickness less than 2 nm suffer from direct tunnelling current or leakage current [54].…”

Fluorinated Graphene Oxide Based Chemiresistive Gas Sensor Targeting NH3 and Other Analytes Under Atmospheric Conditions

“…PMMA is known to promote charge carrier mobility at the semiconductor-insulator interface due to a low trap density and has a dielectric constant of 2.8 and resistivity of 2 x 10 15 Ω m [153]. PMMA thicknesses found in literature tend to be 400-600 nm [154]. PMMA for chemiresistors provides a fibrous structure and low chemical affinity and would provide enhanced molecular trapping for the targeted gas [148].…”