High mobility bottom gate thin film transistors (TFTs) with an amorphous gallium tin zinc oxide $\left(a\text{-}\mathrm{GSZO}\right)$ channel layer have been produced by rf magnetron cosputtering using a gallium zinc oxide (GZO) and tin (Sn) targets. The effect of postannealing temperatures (200, 250, and $300°\mathrm{C}$ ) was evaluated and compared with two series of TFTs produced at room temperature (S1) and $150°\mathrm{C}$ (S2) during the channel deposition. From the results, it was observed that the effect of postannealing is crucial for both series of TFTs either for stability as well as for improving the electrical characteristics. The $a\text{-}\mathrm{GSZO}$ TFTs $(W∕L=50∕50\mu \mathrm{m})$ operate in the enhancement mode ($n$ -type), present a high saturation mobility of $24.6{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ , a subthreshold gate swing voltage of $0.38\mathrm{V}$ /decade, a turn-on voltage of $-0.5\mathrm{V}$ , a threshold voltage of $4.6\mathrm{V}$ , and an $I_{\text{on}}∕I_{\text{off}}$ ratio of $8\times {10}^7$ , satisfying all the requirements to be used as active-matrix backplane.

The aim of the present work was to investigate ultrafast laser surface texturing as a surface treatment of Ti-6Al-4V alloy dental and orthopedic implants to improve osteoblastic commitment of human mesenchymal stem cells (hMSCs). Surface texturing was carried out by direct writing with an Yb:KYW chirped-pulse regenerative amplification laser system with a central wavelength of 1030 nm and a pulse duration of 500 fs. The surface topography and chemical composition were investigated by scanning electron microscopy and x-ray photoelectron spectroscopy, respectively. Three types of surface textures with potential interest to improve implant osseointegration can be produced by this method: laser-induced periodic surface structures (LIPSSs); nanopillars (NPs); and microcolumns covered with LIPSSs, forming a bimodal roughness distribution. The potential of the laser treatment in improving hMSC differentiation was assessed by in vitro study of hMSCs spreading, adhesion, elongation and differentiation using epifluorescence microscopy at different times after cell seeding, after specific stainings and immunostainings. Cell area and focal adhesion area were lower on the laser-textured surfaces than on a polished reference surface. Obviously, the laser-textured surfaces have an impact on cell shape. Osteoblastic commitment was observed independently of the surface topography after 2 weeks of cell seeding. When the cells were cultured (after 4 weeks of seeding) in osteogenic medium, LIPSS- and NP- textured surfaces enhanced matrix mineralization and bone-like nodule formation as compared with polished and microcolumn-textured surfaces. The present work shows that surface nanotextures consisting of LIPSSs and NPs can, potentially, improve hMSC differentiation into an osteoblastic lineage.