Engineering Bilayer AlOx /YAlOx Dielectric Stacks for Hysteresis-Free Switching in Solution-Processed Metal-Oxide Thin-Film Transistors

Solution processing and low-temperature annealing (T < 300°C) of the precursor compounds promise low-cost manufacturing for future applications of flexible oxide electronics. However, thermal budget reduction comes at the expense of increased charge trapping residuals in the dielectric layers, which result in hysteretic switching of transistors. This work reports on a novel bilayer dielectric scheme combining aluminum oxide (AlOx) as a positive charge trapping insulator and yttrium aluminum oxide (YAlOx) as a negative charge trapping dielectric to obtain hysteresis free switching in the solution-processed metal-oxide thin-film transistors. Devices were processed at a thermal budget of 250°C, without an encapsulation layer. The presence of H+ and OH− in the AlOx were found responsible for the hysteresis in the switching, which was suppressed successfully with the thickness optimization of the YAlOx in the dielectric stack. Fabricated devices yield ON/OFF ratios of 106, sub-pA level gate leakage currents, a subthreshold swing of 150 mV/decade, and field-effect mobility of 1.5 cm2/V-sec.

High-sensitivity hybrid PbSe/ITZO thin film-based phototransistor detecting from 2100 nm to 2500 nm near-infrared illumination

We report that high absorption PbSe colloidal quantum dots (QDs) having a peak absorbance beyond 2100 nm were synthesized and incorporated into InSnZnO (ITZO) channel layer-based thin film transistors (TFTs). It was intended that PbSe QDs with proportionally less photocurrent modulation can be remedied by semiconducting and low off-current ITZO-based TFT configuration. Multiple deposition scheme of PbSe QDs on ITZO metal oxide thin film gave rise to nearly linear increase of film thickness with acceptably uniform and smooth surface (less than 10 nm). Hybrid PbSe/ITZO thin film-based phototransistor exhibited the best performance of near infrared (NIR) detection in terms of response time, sensitivity and detectivity as high as 0.38 s, 3.91 and 4.55 × 107 Jones at room temperature, respectively. This is indebted mainly from the effective diffusion of photogenerated carrier from the PbSe surface to ITZO channel layer as well as from the conduction band alignment between them. Therefore, we believe that our hybrid PbSe/ITZO material platform can be widely used to be in favour of incorporation of solution-processed colloidal light absorbing material into the high-performance metal oxide thin film transistor configuration.

Metal Oxide Thin Film Transistor with Nano Inorganic Gate Dielectric : Material Chemistry, Nanoscience, Solution Processing and Electronics

Indium Lead Oxide (ILO) based Metal Oxide Thin Film Transistor (MOTFT) is fabricated with Lead Barium Zirconate (PBZ) gate dielectric. PBZ is formed over doped silicon substrate by cheap sol-gel process. Thin film PBZ is analysed with X-ray Diffraction (XRD), Ultra-Violet Visible Spectra (UV-Vis) and Atomic Force Microscope (AFM). IZO is used as bottom gate to contact Thin Film Transistor (TFT). This device needs only 5V as operating voltage, and so is good for lower electronics <40V. It shows excellent emobility 4.5cm2/V/s, with on/off ratio 5×105 and sub-threshold swing 0.35V/decade.

Enhanced oxygen evolution reaction by stacking single-crystalline freestanding SrRuO3

Transition metal oxide thin film has recently become an attractive platform for enhanced catalytic activity and to perceive the fundamental functions of d electron structure and charge transfer processes. Owing to the long-range lattice ordering and accurate stoichiometry, the single-crystalline transition metal oxide thin film enables the mechanism discussion of electrochemistry down to the atomic level. However, it is technically unviable in the fabrication of transition metal oxide thin film with a substantial surface area and strain condition. Here we report the oxygen evolution reaction enhancement by a stack of multilayer SrRuO3 featured with single-crystallinity, flexibility, and stackability, which was achieved from the rigid heterostructure via a water-dissolution of Sr3Al2O6 sacrifice interlayers. The controllable stack of multilayer SrRuO3 and the emergent high-spin state t2g(3↑)eg(1↑) of Ru efficiently enhances the oxygen evolution reaction activity. Our study provides an approach for fine manipulation of single-crystalline freestanding transition metal oxide morphologically, and an efficient strategy aiming at the extreme enhancement of the electrochemically active surface area and strain condition.