No abstract

No abstract

Thin film transistor which uses an active oxide-semiconductor channel and a ferroelectric-gate insulator, so-called FGT, has wide attention for the application of a new nonvolatile memory owing to its prominent features such as simple structure, high speed and low power consumption. Previously, we have reported on demonstration of the FGTs operation, but the ones developed have channel lengths (L DS ) more than 100 nm, which should be reduced for high-density storage in integration circuits. In this work, a new technique has been proposed to fabricate the sub-100 nm FGT using low-temperature PZT thin film, whose source-drain gap would be mainly created from electron beam lithography, dry etching and ashing. With the new technique, the memory functionality of the fabricated sub-100 nm FGTs are comparable with that of the sub-µm sized FGT. In particular, the ON/OFF current ratio is about 10 4 -10 5 , the memory window is 2.0, 1.8 and 1.7 V, and the field-effect mobility is 0.12, 0.07 and 0.16 cm 2 V −1 s −1 for the L DS of 100, 50, and 30 nm, respectively.

Cupric-oxide-based thin films with various amounts of 0, 1, 2, 3, and 4 wt.% Ni doping were, in turn, deposited on ITO/glass substrates via a solution process. The 0.25 M concentrated solutions of copper (II) acetate monohydrate and nickel acetate tetrahydrate were used as starting materials mixed in ethanol solvent, in order to form the precursors. We obtained that the crystalline structure was not affected by the increase in Ni doping concentration as evidenced by X-ray diffraction patterns. The surface morphology observed by scanning electron microscope pointed out the presence of linked-structure nanoparticles. The influence of Ni doping on the optical bandgap width was evaluated by using ultravioletvisible spectrometry. We found that the optical bandgap should be direct, and it decreased from 2.69 to 2.38 eV for the range doped. Interestingly, we determined the relaxation time of the Ni-doped CuO/ITO/glass structure from measuring the electrochemical impedance spectroscopy, and it was 0.36 s for the undoped film, then gradually decreased to be 0.31, 0.11, 0.1, and 0.04 s with increasing the Ni doping concentration. This achievement result will serve as a foundation for the future photonic researches.

No abstract