Impact of the Cation Composition on the Electrical Performance of Solution-Processed Zinc Tin Oxide Thin-Film Transistors

This study examined the structural, chemical, and electrical properties of solution-processed (Zn,Sn)­O₃ (ZTO) films with various Sn/[Zn+Sn] ratios for potential applications to large-area flat panel displays. ZTO films with a Zn-rich composition had a polycrystalline wurtzite structure. On the other hand, the Sn-rich ZTO films exhibited a rutile structure, where the Zn atom was speculated to replace the Sn site, thereby acting as an acceptor. In the intermediate composition regions (Sn/[Zn+Sn] ratio from 0.28 to 0.48), the ZTO films had an amorphous structure, even after annealing at 450 °C. The electrical transport properties and photobias stability of ZTO thin film transistors (TFTs) were also examined according to the Sn/[Zn+Sn] ratio. The optimal transport property of ZTO TFT was observed for the device with an amorphous structure at a Sn/[Zn+Sn] ratio of 0.48. The mobility, threshold voltage, subthreshold swing, and on/off current ratio were 4.3 cm²/(V s), 0 V, 0.4 V/decade, and 4.1 × 10⁷, respectively. In contrast, the device performance for the ZTO TFTs with either a higher or lower Sn concentration suffered from low mobility and a high off-state current, respectively. The photoelectrical stress measurements showed that the photobias stability of the ZTO TFTs was improved substantially when the ZTO semiconducting films had a lower oxygen vacancy concentration and an amorphous structure. The relevant rationale is discussed based on the phototransition and subsequent migration mechanism from neutral to positively charged oxygen vacancies

Preliminary PET Study of ¹⁸F‑FC119S in Normal and Alzheimer’s Disease Models

To evaluate the efficacy of ¹⁸F-FC119S as a positron emission tomography (PET) radiopharmaceutical for the imaging of Alzheimer’s disease (AD), we studied the drug absorption characteristics and distribution of ¹⁸F-FC119S in normal mice. In addition, we evaluated the specificity of ¹⁸F-FC119S for β-amyloid (Aβ) in the AD group of an APP/PS1 mouse model and compared it with that in the wild-type (WT) group. The behavior of ¹⁸F-FC119S in the normal mice was characteristic of rapid brain uptake and washout patterns. In most organs, including the brain, ¹⁸F-FC119S reached its maximum concentration within 1 min and was excreted via the intestine. Brain PET imaging of ¹⁸F-FC119S showed highly specific binding of the molecule to Aβ in the cortex and hippocampus. The brain uptake and binding values for the AD group were higher than those for the WT group. These results indicated that ¹⁸F-FC119S would be a candidate PET imaging agent for targeting Aβ plaque