Manipulation of epsilon-near-zero wavelength for the optimization of linear and nonlinear absorption by supercritical fluid.

We introduce supercritical fluid (SCF) technology to epsilon-near-zero (ENZ) photonics for the first time and experimentally demonstrate the manipulation of the ENZ wavelength for the enhancement of linear and nonlinear optical absorption in ENZ indium tin oxide (ITO) nanolayer. Inspired by the SCF's applications in repairing defects, reconnecting bonds, introducing dopants, and boosting the performance of microelectronic devices, here, this technique is used to exploit the influence of the electronic properties on optical characteristics. By reducing oxygen vacancies and electron scattering in the SCF oxidation process, the ENZ wavelength is shifted by 23.25 nm, the intrinsic loss is reduced by 20%, and the saturable absorption modulation depth is enhanced by > 30%. The proposed technique offers a time-saving low-temperature technique to optimize the linear and nonlinear absorption performance of plasmonics-based ENZ nanophotonic devices.

Metal Reaction-Induced Bulk-Doping Effect in Forming Conductive Source-Drain Regions of Self-Aligned Top-Gate Amorphous InGaZnO Thin-Film Transistors.

In this paper, the aluminum (Al) treatment-induced doping effect on the formation of conductive source-drain (SD) regions of self-aligned top-gate (SATG) amorphous indium gallium zinc oxide (a-InGaZnO or a-IGZO) thin-film transistors (TFTs) is systematically investigated. Average carrier concentration over 1 × 1020 cm-3 and sheet resistance of around 500 Ω/sq result from the Al reaction doping. It is shown that the doping effect is of bulk despite the treatment at the surface. The doping process is disclosed to be a chemical oxidation-reduction reaction, that generates defects of oxygen vacancies and metal interstitials at the metal/a-IGZO interface. Both the generated oxygen vacancies and metal interstitials act as shallow donors, and the oxygen vacancies diffuse rapidly, leading to the bulk-doping effect. The fabricated SATG a-IGZO TFTs with the Al reaction-doped SD regions exhibit both high performance and excellent stability, featuring a low width-normalized SD resistance of about 10 Ω cm, a decent saturation mobility of 13 cm2/(V s), an off current below 1 × 10-13 A, a threshold voltage of 0.5 V, a slight hysteresis of -0.02 V, and a less than 0.1 V threshold voltage shift under 30 V gate bias stresses for 2000 s.