The aim of this study is to develop a new method for the preparation of Fe3O4@SiO2–An NPs from copperas. The core–shell structures of the nanoparticles and chemical composition have been confirmed by TEM, XRD and FTIR techniques. Fluorescence Enhancement of Fe3O4@SiO2–An NPs with zinc ions was investigated by fluorescence emission spectra. The results indicated that the Fe3O4 NPs with a high purity (Total Fe 72.16 %) were obtained from copperas by chemical co-precipitation method and have a uniform spherical morphology with an average diameter of about 10 nm. The Fe3O4 NPs coated with silica nanoparticles were prepared, and an attempt had been made that the Fe3O4@SiO2 NPs were modified by 3-aminopropyltriethoxysilane and 9-anthranone successively. The recommended mole ratio of ethanol to water and the content of ammonia water added were 4:1 and 25 wt% respectively, which have an obviously effect on the combination of the final well-ordered MNPs with the amino functionalities and reactant components. The functionalized Fe3O4@SiO2–An NPs have a fluorescence property and this fluorescence effect can be enhanced with the Zn2+ ions attachment. Meanwhile, the saturated magnetization of Fe3O4@SiO2–An NPs was 37.8 emug−1 at 25 °C and this fluorescent material exhibited excellent magnetic properties. A new way was therefore provided for the comprehensive utilization of the unmarketable copperas. Moreover, the functionalized Fe3O4@SiO2–An NPs have a big potential in environmental decontamination, medical technology and biological science.

Preparation of novel magnetic fluorescent microspheres from copperas and fluorescence enhancement with zinc ions

Energy band alignment of 2D/3D MoS2/4H-SiC heterostructure modulated by multiple interfacial interactions

This study investigates the performance of SnO2 thin-film transistors (TFTs) fabricated with vertically controlled carrier concentrations using a sol–gel method. In the proposed fabrication method, thin Al layers are deposited on SnO2 surfaces to control carrier concentrations. The deposited Al layers are converted into Al2O3 islands on the SnO2 surfaces, functioning as Al3+ dopant sources after an additional annealing process. Using this process, an oxygen-vacancy-less surface regime inside SnO2 semiconductors is successfully formed. It is demonstrated that this morphology significantly reduces bias stress instability by inhibiting trap and de-trap events at the surface of the back channel of TFTs. The fabricated SnO2 TFTs with oxygen-vacancy (VO)-less surfaces demonstrate a field-effect mobility of 8.49 cm2/Vs and a threshold voltage shift of only −3.84 V during negative bias tests. However, compared to other existing bias stress stable metal-oxide semiconductors, the proposed SnO2 TFTs exhibit only a 3.2% loss in field-effect mobility, alongside improved negative bias stability. 

Improved Negative Bias Stability of Sol–Gel-Processed SnO2 Thin-Film Transistors with Vertically Controlled Carrier Concentrations

We report water-induced nanometer-thin crystalline indium praseodymium oxide (In-Pr-O) thin-film transistors (TFTs) for the first time. This aqueous route enables the formation of dense ultrathin (~6 nm) In-Pr-O thin films with near-atomic smoothness (~0.2 nm). The role of Pr doping is investigated by a battery of experimental techniques. It is revealed that as the Pr doping ratio increases from 0 to 10%, the oxygen vacancy-related defects could be greatly suppressed, leading to the improvement of TFT device characteristics and durability. The optimized In-Pr-O TFT demonstrates state-of-the-art electrical performance with mobility of 17.03 ± 1.19 cm2/Vs and on/off current ratio of ~106 based on Si/SiO2 substrate. This achievement is due to the low electronegativity and standard electrode potential of Pr, the high bond strength of Pr-O, same bixbyite structure of Pr2O3 and In2O3, and In-Pr-O channel’s nanometer-thin and ultrasmooth nature. Therefore, the designed In-Pr-O channel holds great promise for next-generation transistors.

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Water-Induced Nanometer-Thin Crystalline Indium-Praseodymium Oxide Channel Layers for Thin-Film Transistors

Silica-coated iron oxide magnetic nanoparticles(MNP) were synthesized by one-step microemulsion method,and the surface of the compound was aminated by amino-silane coupling agentSubsequently fluorescent molecular anthracene was grafted to the surface via an amide bond The anthracene modified nanoparticles(AMNP) were characterized by XRD,TEM and FTIRThe nanoparticles had a superparamagnetic property at room temperature with the diameter of 9nm around,and that can be easily and effectually seperated from the solution in the presence of an external magnetThe particles had good dispersion in solvent,and fluorescence experiments showed that the particles had excellent selectivity for zinc ionsThe particles exhibited fluorescence increase upon the binding of the Zn~(2+) based on the inhibition of the photoinduced electron transfer quenching mechanismThe fluorescence detection limit for zinc ions was 28571×10~(-5)mol/L

Synthesis of Magnetic Nano Fluorescent Particles Fe_3O_4@SiO_2@An and Identification of Zinc Ions

Two-dimensional (2D) WS2 films were deposited on SiO2 wafers, and the related interfacial properties were investigated by high-resolution X-ray photoelectron spectroscopy (XPS) and first-principles calculations. Using the direct (indirect) method, the valence band offset (VBO) at monolayer WS2/SiO2 interface was found to be 3.97 eV (3.86 eV), and the conduction band offset (CBO) was 2.70 eV (2.81 eV). Furthermore, the VBO (CBO) at bulk WS2/SiO2 interface is found to be about 0.48 eV (0.33 eV) larger due to the inter-layer orbital coupling and splitting of valence and conduction band edges. Therefore, the WS2/SiO2 heterostructure has a Type I energy-band alignment. The band offsets obtained experimentally and theoretically are consistent except the narrower theoretical bandgap of SiO2. The theoretical calculations further reveal a binding energy of 75 meV per S atom and the totally separated partial density of states, indicating a weak interaction and negligible Fermi level pinning effect between WS2 monolayer and SiO2 surface. Our combined experimental and theoretical results provide proof of the sufficient VBOs and CBOs and weak interaction in 2D WS2/SiO2 heterostructures. 

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Interfacial properties of 2D WS2 on SiO2 substrate from X-ray photoelectron spectroscopy and first-principles calculations

Solution-grown indium oxide (In2O3) based thin-film transistors (TFTs) hold good prospects for emerging advanced electronics due to their excellent mobility, prominent transparency, and possibility of low-cost and scalable manufacturing; however, pristine In2O3 TFTs suffer from poor switching characteristics due to intrinsic oxygen-vacancy-related defects and require external doping. According to Shanmugam’s theory, among potential dopants, phosphorus (P) has a large dopant–oxygen bonding strength (EM-O) and high Lewis acid strength (L) that would suppress oxygen-vacancy related defects and mitigate dopant-induced carrier scattering; however, P-doped In2O3 (IPO) TFTs have not yet been demonstrated. Here, we report aqueous solution-grown crystalline IPO TFTs for the first time. It is suggested that the incorporation of P could effectively inhibit oxygen-vacancy-related defects while maintaining high mobility. This work experimentally demonstrates that dopant with high EM-O and L is promising for emerging oxide TFTs.

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Aqueous Solution-Grown Crystalline Phosphorus Doped Indium Oxide for Thin-Film Transistors Applications

Gallium oxide (Ga2O3) is widely used as an ultra-wide bandgap semiconductor in emerging optoelectronics. Recent works show that Ga2O3 could be a promising high- κ dielectric material due to its high thermal stability, excellent moisture resistance, and ease of processing from solution phase. However, the dielectric properties of pristine Ga2O3 could be further improved. Here, aqueous-solution-synthesized Ga2O3 with excellent dielectric properties are achieved by phosphorus (P) incorporation. Using an Ga2O3 dielectric with optimal P (20 at. %) incorporation, oxide thin-film transistors (TFTs) exhibit enhanced performance with a mobility of 20.49 ± 0.32 cm2 V−1 s−1, subthreshold swing of 0.15 ± 0.01 V/dec, current on/off ratio >106, and superior bias stress stability. Systematic analyses show that proper P incorporation considerably reduces oxygen-related defects (oxygen vacancies and hydroxyls) in Ga2O3, resulting in better dielectric and TFT performance.

Qiu Lin

Papers

Water-Induced Nanometer-Thin Crystalline Indium-Praseodymium Oxide Channel Layers for Thin-Film Transistors

Synthesis of Magnetic Nano Fluorescent Particles Fe_3O_4@SiO_2@An and Identification of Zinc Ions

Interfacial properties of 2D WS2 on SiO2 substrate from X-ray photoelectron spectroscopy and first-principles calculations

Aqueous Solution-Grown Crystalline Phosphorus Doped Indium Oxide for Thin-Film Transistors Applications

Aqueous-solution-synthesized gallium oxide dielectrics for high-mobility thin-film transistors enhanced by phosphorus incorporation