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High-Mn austenitic twinning-induced plasticity (TWIP) steels have become nowadays one of the most innovative and attractive materials due to their excellent combination of high strength and high ductility. Along with this, the addition of microalloying elements in the composition of TWIP steels generates a remarkably increase in mechanical properties. The main objective of this research work is to determine the influence of Nb, V, Mo, Ti and Ti/B, as microalloying elements on the microstructure of high-Mn austenitic TWIP steels after as-solutioned and thermomechanical treated conditions. Once melted, TWIP steels were subjected to a homogenization treatment and then hot-rolled with a reduction of 60%. Both processes were carried out at 1200 °C. Afterward, the laminated pieces experimented a solution treatment at 1100 °C and then were water-quenched. Equilibrium phase diagrams of the studied TWIP steels were calculated by using JMatPro. Metallographic characterization was carried out by light optical microscopy and scanning electron microscopy-energy dispersive spectroscopy. X-ray diffraction analyses and Vickers microhardness tests were also performed. In general, results showed that inclusions of MnS and AlN act as nuclei for the microalloying elements precipitation. On the other hand, microalloying additions to TWIP steels resulted in a grain size refinement effect, being the V-bearing TWIP steel the one that presented the highest grain size reduction. X-ray diffraction results showed that austenite phase was stable, as no observation of martensite transformation was noticed. The Ti- and V-bearings TWIP steels exhibited the highest microhardness values.

The fabrication and characterization of optically transparent high performance photolithography-based cadmium sulfide (CdS) thin film transistors (TFT) on polymeric and glass substrates using chemical bath deposition (CBD) is reported. The process utilizes a maximum processing temperature of 115°C, which is compatible with most flexible substrates. The extracted mobility for the fabricated CdS-TFTs ranged from ∼10–18 cm2/V-s with a threshold voltage of ∼1.6–4.8 V and Ion/Ioffratio of ∼107. This carrier mobility is among the highest reported for a fully patterned TFT fabricated with CdS as semiconductor and the first transparent CdS-TFTs built on a flexible substrate with good optical transparency and excellent mechanical flexibility.

We demonstrate an additive ink-jet process to fabricate homogeneous CdS semiconductor films for thin film transistors (TFTs). This process combines in-situ synthesis with ink-jet printing at a maximum processing temperature of 250°C. The solvent in the reaction is used to dissolve the cadmium and sulfur precursors. The reaction to form the CdS films takes place in a solid-state mode. This method does not require preliminary nanoparticles synthesis or organic stabilizers and results in film with near zero precursor waste. TFTs with mobilities of 7.5 × 10−2cm2/V·s, threshold voltage (VT) of 3.4 V and on/off current ratio of 8 × 104were demonstrated.

Cadmium sulfide thin film transistors were demonstrated as the n-type device for use in flexible electronics. CdS thin films were deposited by chemical bath deposition (70°C) on either 100 nm HfO2or SiO2as the gate dielectrics. Common gate transistors with channel lengths of 40–100μmwere fabricated with source and drain aluminum top contacts defined using a shadow mask process. No thermal annealing was performed throughout the device process. X-ray diffraction results clearly show the hexagonal crystalline phase of CdS. The electrical performance of HfO2/CdS-based thin film transistors shows a field effect mobility and threshold voltage of 25cm2V−1s−1and 2 V, respectively. Improvement in carrier mobility is associated with better nucleation and growth of CdS films deposited on HfO2.

Thin PMMA films have been studied extensively for their potential applications as membranes, microlithography and optical applications. PMMA has been recently use like gate dielectric film in OTFT. In this paper we present the structural and electrical characteristics of isotactic PMMA iPMMA thin films prepared by spin coating depositions. The electrical characterization was done using a simple capacitive structure to observe current density across dielectric film and voltage breakdown. The iPMMA films possess low current density across dielectric 1 × 10−8Acm2and the breakdown voltage is higher than 100 V.

The conjugated polymer Poly (3-Hexylthiophene) (P3HT) has attracted much attention as material for the fabrication of Organic Thin Film Transistors (OTFTs) because of its relatively high mobility. However, it has been reported that P3HT increases its conductivity when it is exposed to air or oxygen. In this paper, we studied the change in conductivity of P3HT layers annealed at different temperatures and atmospheres and demonstrate that the increase in conductivity of the P3HT layers after long exposure to air and N2 can be returned to its original value after annealing the device at 363 K in O2 at a pressure of 39.99 Pa (0.3 torr) for 30 min. The procedure was applied to OTFTs fabricated with Poly (3- Hexylthiophene) (P3HT) as active layer and Poly Methyl Methacrylate (PMMA) as dielectric, which were left to long exposure to air and N2, observing that their electrical characteristics returned exactly to their initial values.