Bipolarons rule the short-range terahertz conductivity in electrochemically doped P3HT

Doping of organic semiconductor films enhances their conductivity for applications in organic electronics, thermoelectrics and bioelectronics. However, much remains to be learnt about the properties of the conductive charges in...

Thin nanocrystalline semiconductor films as selective chemical sensors for ammonia, acetone and other donors

Studied are the films of variously doped polycrystalline n-semiconductors (ZnO, SnO2) as selective sensitive elements (SE) of chemical sensors for various gases and vapours (ammonia, acetone, propane, ethanol, hexane, solvent, turpentine etc.) in artificial air. It has been revealed that their conductivity changes under temperature modulation makes possible data processing which identifies the impurities above. This processing is based on nonlinear regression estimation of so called principal parameters which set is unique for every concentration of every of the gases/vapours.

Effects of Iodine Doping on Electrical Characteristics of Solution-Processed Copper Oxide Thin-Film Transistors

In order to implement oxide semiconductor-based complementary circuits, the improvement of the electrical properties of p-type oxide semiconductors and the performance of p-type oxide TFTs is certainly required. In this study, we report the effects of iodine doping on the structural and electrical characteristics of copper oxide (CuO) semiconductor films and the TFT performance. The CuO semiconductor films were fabricated using copper(II) acetate hydrate as a precursor to solution processing, and iodine doping was performed using vapor sublimated from solid iodine. Doped iodine penetrated the CuO film through grain boundaries, thereby inducing tensile stress in the film and increasing the film’s thickness. Iodine doping contributed to the improvement of the electrical properties of the solution-processed CuO semiconductor including increases in Hall mobility and hole-carrier concentration and a decrease in electrical resistivity. The CuO TFTs exhibited a conduction channel formation by holes, that is, p-type operation characteristics, and the TFT performance improved after iodine doping. Iodine doping was also found to be effective in reducing the counterclockwise hysteresis in the transfer characteristics of CuO TFTs. These results are explained by physicochemical reactions in which iodine replaces oxygen vacancies and oxygen atoms through the formation of iodide anions in CuO.

Deposit and Characterization of Semiconductor Films Based on Maleiperinone and Polymeric Matrix of (Poly(3,4-Ethylenedioxythiophene) Polystyrene Sulfonate)

The development of small semiconductor molecules such as the maleiperinone, have gained importance due to their applications in optoelectronics. In this work semiconductor films composed by a polymer matrix of PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) and maleiperinone were manufactured. The films used in the studies were deposited by vacuum evaporation and spin-coating techniques. Atomic force microscopy (AFM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Infrared spectroscopy were used for the analysis of morphological and structural films. The fundamental and the onset of the direct and indirect band gaps were also obtained by UV-vis spectroscopy. The band-model theory and the Density-functional theory (DFT) calculations were applied to determine the optical parameters. The dipole moment is 3.33 Db, and the high polarity gives a signal of the heterogeneous charge distribution along the structure of maleiperinone. Simple devices were made from the films and their electrical behavior was subsequently evaluated. The presence of the polymer decreased the energy barrier between the film and the anode, favoring the transport of charges in the device. Graphene decreased the absorption and its ohmic behavior make it a candidate to be used as a transparent electrode in optoelectronic devices. Finally, the MoO3 provides a behavior similar to a dielectric.

Low-Temperature Fabrication of IZO Thin Film for Flexible Transistors

Solution-processed thin film transistors (TFTs) used in flexible electronics require them to be fabricated under low temperature. Ultraviolet (UV) treatment is an effective method to transform the solution precursors into dense semiconductor films. In our work, high-quality indium zinc oxide (IZO) thin films were prepared from nitrate-based precursors after UV treatment at room temperature. After UV treatment, the structure of IZO thin films was gradually rearranged, resulting in good M–O–M network formation and bonds. TFTs using IZO as a channel layer were also fabricated on Si and Polyimide (PI) substrate. The field effect mobility, threshold voltage (Vth), and subthreshold swing (SS) for rigid and flexible IZO TFTs are 14.3 and 9.5 cm2/Vs, 1.1 and 1.7 V, and 0.13 and 0.15 V/dec., respectively. This low-temperature processed route will definitely contribute to flexible electronics fabrication.