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In this letter, high-performance zinc oxide thin-film transistors (ZnO TFTs) have been fabricated on Si substrate by atomic layer deposition (ALD) at 190 °C. The field-effect mobility ( $\mu _{FE}$ ) can be improved from 18.5 cm2/ $\text{V}\cdot \text{s}$ to a record high 43.2 cm2/ $\text{V}\cdot \text{s}$ while maintaining a large $\text{I}_{{\mathrm {on}}}/\text{I}_{{\mathrm {off}}}$ ratio of $5\times 10^{9}$ after rapid thermal annealing (RTA) under vacuum at 350 °C. The excellent performance can be attributed to the improvement in the ZnO channel and the interface. The oxygen vacancy ratio in ZnO increases from 36.2% to 40.0%. The interface trap density ( $\text{N}_{it}$ ) between silicon oxide (SiO2) and ZnO decreases from $5.1 \times 10^{11}$ eV $^{-1}$ cm $^{-2}$ to $1.4\times 10^{11}$ eV $^{-1}$ cm $^{-2}$ . Furthermore, the oxide trap density ( $\text{N}_{{\mathrm {ot}}}$ ) of the SiO2 dielectric reduces from $3.7\times 10^{19}$ eV $^{-1}$ cm $^{-3}$ to $1.1\times 10^{19}$ eV $^{-1}$ cm $^{-3}$ . Finally, we systematically study the electrical performance of the annealed ZnO device at measurement temperature from room temperature of 20 °C to a much higher temperature of 180 °C without device failure.

Although indium tin oxide (ITO) is widely used in optoelectronics due to its high optical transmittance and electrical conductivity, its degenerate doping limits exploitation as a semiconduction material. In this work, we created short-channel active transistors based on an ultra-thin (down to 4 nm) ITO channel and a high-quality, lanthanum-doped hafnium oxide dielectric of equivalent oxide thickness of 0.8 nm, with performance comparative to that of existing metal oxides and emerging two-dimensional materials. Short-channel immunity, with a subthreshold slope of 66 mV per decade, off-state current 10 GHz, have been demonstrated. The unique wide bandgap and low dielectric constant of ITO provide prospects for future scaling below the 5-nm regime for advanced low-power electronics. Controlled physical vapour deposition of indium tin oxide layers with thickness down to 4 nm allows the use of these materials as active channels in high-performing transistors for digital and radiofrequency electronics.

Flexible zinc oxide thin film transistors (ZnO TFTs) with a mobility of $ {13}~\text {cm}^{2}/\text {V}\cdot \text {s}$ and an I $_{\text {on}}/\text{I}_{\text {off}}$ ratio of $ {1.5}\times {10}^{8}$ have been fabricated on polyimide substrate, where the ZnO channel is deposited by atomic layer deposition (ALD) at 140 °C. High bending stability has been achieved due to excellent interface quality between alumina (Al2O3) dielectric and ZnO channel with a sharp interface topography. The flexible ZnO device exhibits excellent electrical characteristics even after being bent for 200 000 cycles with a tensile strain of 0.63%. Electrical measurement under a high tensile strain of 2.08% has also been carried out. Moreover, the electrical performance dependence of flexible ZnO TFTs with a tensile strain of 0.78% on temperature from 20 °C to 140 °C has been investigated for the first time.

Nano TiO2 particles, as white electrophoretic particles of electronic paper, have the advantages of high chemical stability and good optical performance. But their excessive density and surface hydrophilicity are not conducive to the uniform dispersion of the electrophoretic particles in the organic dispersion. Nano TiO2 particles are easy to aggregate and precipitate in the electrophoresis solution. In this paper, a variety of methods for surface modification of TiO2 particles were reviewed to reduce the density of nano TiO2 microspheres and increase their surface charge to obtain stable nano TiO2 microsphere electrophoretic suspension. The development prospect of electronic paper is discussed.

In this study, a novel type of donor-acceptor (D-A dyad) system discotic liquid crystal was designed and synthesized, Which based on triphenylene and perylene units and connected by flexible alkyl chains. Confirm the structure of the compound using 1H-NMR and FT-IR, and its mesogenic properties were characterized by differential scanning calorimetry (DSC) and polarized light microscope (POM). The synthesis of this compound enriches the research on the types and properties of disk liquid crystals, and its excellent mesogenic properties provide useful information for the application of organic photoelectric devices.

In this thesis, the compound 3,6-diethylethyl-2,7,10,11-tetrapentyloxy-triphenylene (36TPE) was designed and synthesized. The mixture 36TPE/TCNQ was obtained by mixing 36TPE with 7,7,8,8-tetrachyanobenzoquinone (TCNQ) at molar ratio 1:1. The spectral characteristics were studied by FT-IR and UV-vis. Its mesomorphism was investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction. The ionization potential energy was measured by the ionization potential energy tester. The experimental results showed that the dopant 36TPE/TCNQ forms a charge transfer complex and 36TPE/TCNQ formed a hexagonal columnar phase; the HOMO value of the complex is between the electron donor and the electron acceptor, and the value of LUMO was lower than the value of the donor and acceptor.

Tunable bandgap can be induced in Bernal-stacked bilayer graphene by a perpendicularly electric displacement field. Here, we carry out a comprehensive study on the material synthesis of CVD Bernal-stacked bilayer graphene and devices for amplifying and mixing at high frequencies. The transistors show large output current density with excellent current saturation with high intrinsic voltage gain up to 77. Positive extrinsic forward power gain | S21|2 has been obtained up to 5.6 GHz as well as high conversion gain of -7 dB for the mixers. The conversion gain dependence on tunable on/off ratio of the transistors has also been discussed.

Low ductility has long been the bottleneck for high temperature application of TiAl alloys. It is reported that grain refinement through boride could improve its mechanical property. However, this refinement is suppressed at high cooling rate. This article delineates for the first time an in situ observation by synchrotron X-ray diffraction. It illustrates the mechanism of competitive nucleation and grain growth of Burgers and non-Burgers α grains during β → α transformation in a Ti–45Al–5Nb–0.2C–0.2B alloy (TNB-V5). Comparing with those in base material, the volume fraction and size of borides are significantly reduced in the welding zone. The non-Burgers α grains nucleate earlier than Burgers α. However, Burgers α grains grow much faster than non-Burgers α during β → α transformation in the welding zone, due to a high thermodynamic driving force of Burgers α grains. No orientation relationships between α and borides or between β and borides are observed in the fast cooling.

Disclinations are topological singularities of molecular arrangement in liquid crystals, which typically occur when the average orientation of molecules makes a π rotation along a fictitious closed loop taken inside the liquid crystal. Depending on the sense of molecular rotation, the disclination lines are either of 1/2 or −1/2 strength. When two disclination lines with the opposite strength meet, they are annihilated without trace. It is hence generally considered difficult in the nematic phase to stabilize a condensed array of free-standing disclination lines without the aid of topological objects like colloidal inclusions. Here we show that a free-standing web of 1/2-strength twist disclination lines can be stably formed in thin liquid crystal cells by means of a judicious combination of orientationally patterned confining surfaces fabricated by the micropatterned photoalignment technique. Theoretical model indicates that disclination lines are held apart at the intersection by a repulsive force generated by the Frank elasticity., Disclination lines are topological defects in molecular orientation widely found in liquid crystals. Here Wang et al. use a surface patterning technique to produce a very stable freestanding 3D array of ½ twist disclinations, which could be exploited in a variety of nanometre scale applications.

In this work, ultrathin indium tin oxide (ITO) radio frequency (RF) transistors have been demonstrated for the first time, where inverted gate structure are used with a flexible polyimide substrate using magnetron sputtering at a thermal budget below 200 °C. The 160 nm channel length device exhibits excellent DC characteristics, including mobility of 26 cm2/V•s and an I on /I off ratio of 6.6×108. A record-high extrinsic cut-off frequency (f T ) of 2.1 GHz and an extrinsic maximum oscillation frequency (f max ) of 3.7 GHz have also been obtained, which are more than one order of magnitude higher than previous results on flexible substrate. A high conversion gain of -20.9 dB has been achieved for the gigahertz frequency mixer based on flexible ITO RF transistor. Moreover, the stability of DC and RF performance under different bending conditions up to 50,000 bending cycles or down to 1 mm bending radius are studied without device failure.

In this paper, we report high-speed ultrathin-body (3.5 nm) indium-tin-oxide (ITO) transistors using high-k HfLaO dielectrics with a thickness of 5 nm. Because of its low dielectric constant and large bandgap, ITO is a promising channel material for scaling below the 5 nm regime for advanced low-power electronics with excellent short-channel-immunity. Here, we fabricate sub-100-nm channel length ITO transistors with ultrahigh on/off ratio near 1011 and ultralow off-state current below 10 fA/μm. The 15-nm-long ITO transistor exhibits high performance with the maximum on-state current of 970 μA/μm and peak g m of 400 μS/μm at V ds = 0.5 V. NAND, NOR, and SRAM based on enhancement/depletion mode (E/D) inverters have achieved full rail-to-rail output characteristics and stable memory function. Finally, We demonstrated a stage delay of 0.49 ns/stage for a 5-stage ring oscillator based on bootstrapped mode (BST) inverter, which is the best among all results based on metal-oxides transistors.

Phthalocyanines exhibit distinct physicochemical properties by modifying the π-conjugated system which makes them as the suitable candidates for various applications. Recently, we synthesized and characterized rhenium phthalocyanine (Re1Pc, Re2Pc) and rhenium tetraazaporphyrin (Re1TAP, Re2TAP) complexes (Figure 1 (a)).1 In terms of electrochemical properties (Figure 1 (c)), compared to the corresponding Zn complexes (ZnPc, ZnTAP), both the first oxidation and the first reduction potentials of Re complexes (Re1Pc, Re2Pc, Re1TAP, Re2TAP) shift to the positive side owing to the introduction of electron-deficient [Re(CO)3]+ unit(s). On the other hand, by reducing the π-conjugated system from Pc to TAP, more positive oxidation potentials are observed in the ReTAP complexes. This trend is consistent with the changes in the calculated HOMO and LUMO energy levels (Figure 1 (b)). Notably, the positively shifted oxidation potentials of these complexes significantly improve the tolerance towards oxidation, which is essential for various applications. In the electronic absorption spectra of these Re complexes, the unsymmetric coordination of the [Re(CO)3]+ unit(s) concomitantly produces a remarkable red shift of the Q band. Also, in ReTAP complexes, the broadening of the Q bands is uniquely observed. DFT calculations indicate that the macrocycle skeletons in Pc and TAP are highly distorted, in contrast to the high stability towards oxidation. In the presentation, the distorted structures will be discussed in detail. [1] K. Murata, Y. Koike, K. Ishii, Chem. Commun., 2020, 56, 13760-13763. Figure 1. (a) Molecular structures of RePc and ReTAP complexes. (b) Energy plots of the molecular orbitals and (c) the electrochemical results of MPc and MTAP complexes. Figure 1

Steel skeleton supported membrane structure is the major structural form of membrane structure, accounting for more than 50%. The structural characteristics of membrane structure itself determine that the analysis of its self-vibration characteristics is very important in the design process. According to the von Karman’s large deflection theory and the D’Alembert’s principle, the governing equations of nonlinear viscous damping vibration of the skeleton supported orthotropic membrane structure were proposed. By applying the Galerkin method and the KBM perturbation means of obtaining the analytical solutions of frequency function, displacement function and mode function of damped nonlinear and linear free vibration of simply supported orthotropic membrane structures on four sides were obtained. In addition, it can be known by example analysis that the transverse stiffness of membrane structure can be improved by increasing prestress and rise span ratio in the practical engineering, and while the influence of geometrically nonlinear, orthotropic, damping and prestress on the dynamic feature of membrane structure must be fully considered. This paper provides some theoretical references for the wind-induced dynamic stability calculation and wind-resistant design of the steel skeleton supported membrane structure.

In this paper, we report GaN MOS-HEMTs with high quality atomic-layer-deposited HfLaO x as gate dielectric. The threshold voltage of the recessed gate MOS-HEMT can be enhanced from -6.2 V to 0.8 V. The E-mode GaN MOS-HEMT exhibits ideal subthreshold swing $\sim ~66$ mV/dec and high on-off ratio of $1.2\times 10^{10}.$ Conductance method has been applied to reveal interface trap density $D_{\mathrm {it}}$ distribution between high-k/III-N interface. Effective mobility of D-mode and E-mode MOS-HEMTs are $1958\,\mathrm{cm}^{2}/V \cdot\mathrm{s}$ and $1483\,\mathrm{cm}^{2}/\mathrm{V} \cdot \mathrm{s}$, respectively. A high breakdown voltage of 840 V was achieved, thanks to suppressed gate leakage. The specific on-resistance of E-mode device is 1.86 $\text{m}\omega \cdot \mathrm{cm}^{2}$, which results in high power figure of merit (BV2/R on,sp ) of 380 MW/cm2.

The crystal morphology of RDX largely affects its stability, dispersion, and energy output. The influence of the solvent on the crystal morphology plays a key role. A molecular dynamics method is used to calculate the interaction energies between five important crystal planes of RDX and the solvent layer under the action of cyclohexanone/water and dimethyl sulfoxide/acetone mixed solvents. The attachment energies are modified and the crystal morphologies of RDX under the effect of different volume ratios of the mixed solvents are predicted. The results show that the five important crystal planes of RDX are attracted to the two mixed solvents. Compared with the (111) and (210) faces, the (200), (002), and (020) faces show more obvious growth phenomena under the action of the two mixed solvents. When the mixed solvent is cyclohexanone/water, the lower the proportion of cyclohexanone, the closer the RDX crystal morphology is to spherical. When the mixed solvent is dimethyl sulfoxide/acetone, if spheroidal RDX is desired, the proportion of acetone should be greater than or equal to the proportion of dimethyl sulfoxide. The radial distribution functions between O atoms of the (111) face and H atoms in the two mixed solvents under different volume ratios are analyzed to explore the interaction forces at the interfaces.

We demonstrated the stabilization of blue phase (BP) liquid crystal by doping the colloidal particles. Temperature range studies were conducted with imaging through the polarized optical microscope (POM). The BP liquid crystal temperature range was increased up to 3.1°C with 0.76% colloidal particles in BP, and then decreased with increasing concentration of colloidal particles in the BP mixture. Reflectance measurements showed the greatest wavelength shifting occurred with 1.84% colloidal particles in BP mixture. In the field-induced optical Kerr effect, the optimization in the colloidal particles doped BP LC device also decreased in threshold voltage (Vth) from 34.2V of non-doped BP LC, to 32.2V of the doped BP LC.

The macromolecular pigment-protein complex has the merit of high efficiency for light-energy capture and transfer after long-term photosynthetic evolution. Here bio-dyes of A.platensis photosystem I (PSI) and spinach light-harvesting complex II (LHCII) are spontaneously sensitized on three types of designed TiO2 films, to assess the effects of pigment-protein complex on the performance of bio-dye sensitized solar cells (SSC). Adsorption models of bio-dyes are proposed based on the 3D structures of PSI and LHCII and the size of particles and inner pores in the TiO2 film. PSI shows its merit of high efficiency for captured energy transfer, charge separation and transfer in the electron transfer chain (ETC) and electron injection from FB to the TiO2 conducting band. After optimization, the best short current (JSC) and photoelectric conversion efficiency (η) of PSI-SSC and LHCII-SSC are 1.31 mA cm-2 and 0.47% and 1.51 mA cm-2 and 0.52%, respectively. The potential for further improvement of this PSI based SSC is significant and could lead to better utilization of solar energy.

We report on dispersion of a small amount of colloids in a blue phase liquid crystal, and the blue-phases were found to exhibit extended temperature range. The stabilized temperature range of the blue phase was a function of their most effective concentration, different sizes of colloid particles and shape of colloidal particles. The temperature range was probed and determined and the temperature range of the blue phases was found to decrease as the colloidal particle size increased. Additionally, the temperature dependent of Bragg wavelength peak was found to redshifted in the colloidal-BP mixtures. The electro-optical results, especially the switching voltage and response time suggested that concentration and size of dispersed colloids modified the elastic energy of the blue phase liquid crystal composites and led to a lower switching voltage.

Compared with the conventional deposition techniques used for the epitaxial growth of metallic structures on a bulk substrate, wet-chemical synthesis based on the dispersible template offers several advantages, including relatively low cost, high throughput, and the capability to prepare metal nanostructures with controllable size and morphology. Here we demonstrate that the solution-processable two-dimensional MoS(2) nanosheet can be used to direct the epitaxial growth of Pd, Pt and Ag nanostructures at ambient conditions. These nanostructures show the major (111) and (101) orientations on the MoS(2)(001) surface. Importantly, the Pt-MoS(2) hybrid nanomaterials exhibit much higher electrocatalytic activity towards the hydrogen evolution reaction compared with the commercial Pt catalysts with the same Pt loading. We believe that nanosheet-templated epitaxial growth of nanostructures via wet-chemical reaction is a promising strategy towards the facile and high-yield production of novel functional materials.