Indium oxide doped with tin oxide, ITO, has been extensively used as the transparent conductive electrode in display industry, and also been utilized on polymeric substrate for flexible display. The polymeric material used in flexible display has its flexibility and lightweight compared to glass-based substrate. However, it does not completely meet with the requirements in mechanical properties. The ion irradiations modify the polymeric surface that can be expected to improve its adhesion property. In this study, linear ion source was developed to treat the polymeric surface, and then ITO thin film was deposited by sputter deposition commonly utilized in display industry. Atomic Force Microscope was used to analyze the physical transformation of surface structure after the various argon and oxygen ion irradiated. Finally, the scratch testing showed the adhesive strength improved between ITO thin film and polymeric substrate when surface modified by optimum ion irradiation. Moreover, linear ion source provides the good uniformity of surface treatment and is very suitable for production-scale process.

We present recent advances on spin-on polymers as gate dielectric for thin film transistors. We have developed film type I with significantly improved dielectric properties. At a curing temperature of 250 °C, the dielectric constant is 3.46, the breakdown voltage is 4.10 MV/cm at 1 μA/cm2, the leakage current is 4.9 × 10−8 A/cm2 at 2.5 MV/cm, and the CV hysteresis is 3.4 V. At a curing temperature of 425 °C, the dielectric constant, the breakdown voltage, the leakage current, and the CV hysteresis are 3.2, 4.73 MV/cm, 2.6 × 10−8 A/cm2, and 0.44 V respectively.

In the thin film transistor fabrication process, tin doped indium oxide (ITO) or zinc doped indium oxide (IZO) film can be easily exposed to hydrogen-containing plasma during the deposition of silicon nitride (SiNx) film. By this exposure, ITO or IZO can be easily reduced into its corresponding metallic element such as indium, which degrades the optical transmittance and the conductivity. In this study, SiNx was deposited onto ITO or IZO film, and the oxygen reduction of ITO or IZO during PECVD SiNx deposition was analyzed to clarify this phenomenon. The oxygen reduction during PECVD SiNx deposition is mainly induced by decomposed NH3 gas. However, the progress of ITO reduction is different from that of IZO reduction, due to the different atomic composition of In2O3 in the composite and the different critical temperature of reduction initiation between indium oxide, tin oxide, and zinc oxide.

The configuration of the OLED device is like this : ITO/PEDOT:PSS(Ag nanoparticle) /NPB/Alq3/Al

The effect of Ag nanoparticles in the hole injection layer on the performance of Organic Light Emitting Diodes(OLED) was investigated.

The hole mobility in the hole injection layer seems to be increased by Ag nanoparticles.

The increased current in the hole injection layer increased the emission efficiency of the OLED.

Initially, we try to incorporate silver nanoparticles(diameter:30nm) directly into the hole injection layer. However the Ag nanoparticles are aggregated into big particles, ( size 1∼2 μm). We can confirm this behavior by the optical microscope. Thus, PEDOT:PSS/Ag nanoparticles solutions were filtered before spin-coating and big particles were eliminated by this process.

The several silver nanoparticles concentration were selected (0.05, 0.1, 0.25 wt % of the silver nanoparticles was mixed with PEDOT;PSS solutions). Theses solutions were spin-coated on the ITO layer with 3000 rpm for 60 secs. The spin coated Ag, PEDOT:PSS solutions were heat treated at 100 °C in 30 min. The big Ag agglomerate was not observed in the optical microscope. Then the thermal evaporation of the NPB and Alq3 layer was conducted.

The current-voltage relation was measured for the device and compared with the OLED device without Ag particle. The lumninance of the devices are also measured. The Ag nanoparticle increases the deriving current and thus increases the quantum efficiency of the OLED.

Thin films of indium molybdenum oxide (IMO) were rf sputtered onto glass substrates at room temperature. The films were studied as a function of sputtering power (ranging 40 – 180 W) and sputtering time (ranging 2.5 – 20 min). Thickness of the films found varied between 50 – 400 nm. The films were characterized for their structural (XRD), electrical (Hall measurements) and optical (Transmittance spectra) properties. XRD studies revealed that the films are amorphous for the sputtering power ≤ 100 W and deposition time ≤ 5 min. All the other films are polycrystalline and the strongest refection along (222) plane showing a preferential orientation. A minimum bulk resistivity of 2.65 × 10−3 Ω-cm and a maximum carrier concentration of 4.16 × 1020 cm−3 have been obtained for the films sputtered at 180 W (10 min). Whereas maximum mobility (19.5 cm2 V−1 s−1) has been obtained for the films sputtered at 80 W (10 min). A maximum visible transmittance of 90 % (500 nm) has been obtained for the films sputtered at 80 W (10 min) with a minimum of 27 % for those sputtered at 180 W. The optical band gap of the films found varying between 3.75 and 3.90 eV for various sputtering parameters.

Sol-gel derived Nb2O5 thin films crystallize to a stable hexagonal phase on annealing at 600°C in air. These films have been intercalated with Mg2+ ions for the first time and the structural and the optical changes on intercalation have been reported. Films were intercalated and deintercalated with Mg2+ ions in galvanostatic mode. Mg intercalated films show about 35% transmittance variations in the entire spectral range. The FTIR studies show the formation of Mg-O-Nb bonds along with the formation of Nb-OH and Mg-O bonds. Small quantities of water is adsorbed during intercalation resulting in the formation of Mg(OH)2. The coloration is completely reversible on deintercalation. Formation of MgNb2O6 phase is seen on intercalation with 1M concentration of the electrolyte, which is found to be 'x' dependent, where ‘x’ is the ratio of the intercalated ions to the Nb atoms. 0.1 M electrolyte does not show the formation of this phase.

We have successfully used a transfer printing technique to directly transfer vacuum-filtered nanotube film to glass and plastic substrates. Our typical SWNT-film has a transparency of ∼80% and a sheet resistance around 400 Ohm/square. Further improvement to the nanotube film includes SOCl2 doping and PEDOT passivation, which significantly improve the sheet conductance and surface quality of the nanotube films. We have applied the optimized SWNT films as hole injection electrodes to demonstrate OLEDs on both rigid glass and flexible substrates.

Phase formation in ternary system of complex Sc, Na and Li phosphates was studied at 950°C and synthesis of new phases of definite composition was carried out. Obtained samples were investigated with X-ray powder diffraction, infrared and impedance spectroscopy. Compositions of fields of homogeneity with the NASICON-like structure were discovered. Temperature dependency of ionic conductivity was measured.

Interest is widespread in flexible thin-film transistor backplanes made on clear polymer foil, which could be universally employed for a variety of applications. All ultralow process temperatures, plastic compatible thin film transistor (TFT) technologies battle short or long term device instabilities. The quality and stability of amorphous silicon thin-film transistors (a-Si:H TFTs) improves with increasing process temperature. TFT stacks deposited at less than 250°C by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) exhibit higher threshold voltage shifts after gate bias stressing than stacks deposited at ∼300°C in the active matrix liquid-crystal display (AMLCD) industry [1]. Therefore, optically clear plastic (CP) substrates are desired that tolerate high process temperatures. The first step in a-Si:H TFT fabrication on a polymer is the deposition of a planarizing barrier and adhesion layer. For this purpose we have been using silicon nitride (SiNx) grown by PECVD.

This paper discusses the substrate preparation and SiNx deposition for the process temperature of 250°C. We study the mechanical strain in the SiNx film on the CP substrate, as a function of RF power. Earlier work has shown that SiNx films deposited at low RF power are under tensile strain, and become increasingly compressed as the deposition power is raised [2]. Additionally, at very high deposition power the substrate is bombarded at the beginning of film growth to achieve good film adhesion. The goal is to identify the correct processing conditions at which the total mismatch strain between the film and the substrate is minimized, to keep the film/substrate composite flat and avoid mechanical fracture as well as peeling due to poor adhesion. Optimal deposition conditions were identified to obtain crack-free SiNx barrier layers. The barrier layers were tested by fabricating a-Si:H TFTs on them at 250°C.