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Solution processible poly(4-vinylphenol) is employed as a transistor dielectric material for low cost processing on flexible substrates at low temperatures. A 6,13-bis (triisopropylsilylethynyl) (TIPS) pentacene–graphene hybrid semiconductor is drop cast to fabricate bottom-gate and bottom-contact field-effect transistor devices on flexible and glass substrates under an ambient air environment. A few layers of graphene flakes increase the area in the conduction channel, and form bridge connections between the crystalline regions of the semiconductor layer which can change the surface morphology of TIPS pentacene films. The TIPS pentacene–graphene hybrid semiconductor-based organic thin film transistors (OTFTs) cross-linked with a poly(4-vinylphenol) gate dielectric exhibit an effective field-effect mobility of 0.076 cm2 V−1 s−1 and a threshold voltage of −0.7 V at Vgs = −40 V. By contrast, typical TIPS pentacene shows four times lower mobility of 0.019 cm2 V−1 s−1 and a threshold voltage of 5 V. The graphene/TIPS pentacene hybrids presented in this paper can enhance the electrical characteristics of OTFTs due to their high crystallinity, uniform large-grain distribution, and effective reduction of crystal misorientation of the organic semiconductor layer, as confirmed by x-ray diffraction spectroscopy, atomic force microscopy, and optical microscopy studies. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have emerged as a promising technology for renewable energy generation due to their low cost, lightweight, flexibility, and compatibility with roll-to-roll manufacturing. However, OSCs still face challenges in achieving high power conversion efficiency (PCE) due to various factors, including recombination loss. In this study, we investigated the effect of introducing a layer of eight atomic percent gadolinium-doped zinc oxide (Zn0.92Gd0.08O) between the poly(3-hexylthiophene) (P3HT): [6,6]-phenyl butyric acid methyl ester (PCBM) active layer and the fluorine-doped tin oxide (FTO) electrode of the OSC. The reference cell, which has an Au/P3HT:PCBM/ZnO/FTO structure, exhibits a PCE of 0.52%. Remarkably, when the Zn0.92Gd0.08O layer was inserted (Au/P3HT:PCBM/Zn0.92Gd0.08O/FTO), the PCE increased significantly to 3.42%, which is more than six times the increase. Through further analysis, we present that the insertion of the Zn0.92Gd0.08O layer induces spin polarization in the P3HT:PCBM layer, leading to enhanced charge transport and reducing the recombination rate. Based on the findings, it can be concluded that the Zn0.92Gd0.08O film can potentially improve OSC performance. [ABSTRACT FROM AUTHOR]

Trivalent metal-doped TiO2 thin films have been extensively investigated in gas sensor applications. The trivalent metal dopants are Al, Y and Gd. The trilayer fabrication of a gas sensor consists of a thin film, sputtered TiO2 and Au nanoparticles. The characteristics of the gas sensing properties are strongly correlated with the annealing temperature, film thickness, type of doping and deposition method. The subsequent properties are presented - the crystalline structure, grain size, roughness, strain, stress and defects. Thin films have been developed with concentrations of O2 gas up to 10 sccm. A response time for O2 gas in milliseconds was obtained at room temperature. Al doped TiO2 thin film have a faster response time operating at room temperature compared with other thin films. Oxygen vacancy defects also contribute to the speed of the response time for a gas sensor. [ABSTRACT FROM AUTHOR]

This work addresses the design, fabrication, and implementation of an RF energy harvester 2.45 GHz using a compact rectenna. Our proposed rectenna focuses on development of an antenna array and rectifier circuit. The proposed rectenna is fabricated using FR4 substrate with its overall size of 12.24 cm × 18.17 cm with a thickness of 1.6 mm. The measured results show that a 10 dB bandwidth covering in 2374-2549 MHz (175 MHz) with center frequency 2415 MHz at S11 of −18.2 dB. There is a bandwidth enhancement of 57.6% compared to the single antenna. Gaining of the antenna array is 6 dB that is double a single antenna gain. Spatial diversity technique in antenna array yields a bigger antenna gain thereby increasing the received power level. Experimental measurements are carried out that the rectenna is placed indoor (LOS) at 5 m and outdoor (NLOS) at 15 m. Furthermore, we also explore the rectifier circuit that to maximize the output voltage. The received RF power that transmitted from WiFi router is −55 dBm (0.15 nW/cm2) at 5 m and −59 dBm (0.06 nW/cm2) at 15 m, respectively. The output voltages are achieved that 1092.5 mV at a distance of 5 m (LOS) and 5.48 mV at a distance of 15 m (NLOS). The highest RF-DC conversion efficiency of our proposed rectenna reaches 77.6%. The rectenna potentially meets all requirements to power up the IoT applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gd-doped ZnO films were synthesized by sol–gel spin coating technique. • Anomalous Hall Effect signal reveals intrinsic ferromagnetism and existence spin polarization in Gd-doped ZnO films. • MFM qualitatively proves the existence of spin polarization in the Gd-doped ZnO films. • Optical band-gap results indicate the existence of strong spin-exchange interaction. In this study, Gd-doped ZnO films with different Gd concentrations were synthesized by sol–gel spin coating technique. The intrinsic ferromagnetism and the existence of spin-polarized carriers in Gd-doped ZnO films were investigated using Hall effect and MFM. The Hall effect and MFM measurement detect the AHE signal and the magnetic domain structure, respectively, proving intrinsic FM and the existence the spin polarization in the films. XRD and FTIR analysis showed that the crystal structure of Gd-doped ZnO films is a hexagonal wurtzite structure. The optical band gap is found red-shifted from 3.265 to 3.227 eV with the increase in Gd doping concentration, indicating the existence of strong spin-exchange interaction. EDX analysis confirmed the presence of Gd in the ZnO matrix. Based on the finding, we proposed 8 at. % Gd-doped ZnO film is optimal, potentially used as a spin injector for organic spintronic devices. [ABSTRACT FROM AUTHOR]

Abstract: SrTiO3 thin films were deposited on AlGaN/GaN wafer by a simple, low-temperature liquid-phase deposition (LPD) method, and applied as the gate dielectric in metal oxide semiconductor high electron mobility transistor (MOSHEMT). X-ray diffraction and electrical characteristics were measured to investigate the film phase and leakage current. AlGaN/GaN MOSHEMTs with 20nm-thick SrTiO3 as the gate dielectric were also fabricated. Compared with its counterpart HEMT, MOSHEMT shows lower leakage current and larger breakdown voltage. The suppressed gate leakage current improves both I on/I off ratio and subthreshold slope. Larger maximum drain current density could be achieved with higher V on in the MOSHEMT. Flatter transconductance and wider gate voltage swing of the MOSHEMT demonstrate better device linearity. The lower low-frequency noise is obtained due to the lower surface states. [Copyright &y& Elsevier]

High-performance pentacene-based thin-film transistors and inverters with solution-processed barium titanate (BTO) insulators are demonstrated. The current–voltage characteristics of the transistors show high mobility of 9.53 \cm^2\V^-1\s^-1 at smaller VG = -\3.5\ \V and VD = -\5\ \V, a low threshold voltage of -1.5 V, and a subthreshold slope of 599 mV/dec. Large grain and small crystalline sizes are observed from atomic force microscopy images and X-ray diffraction analysis of pentacene films. The results are verified through Raman spectroscopy and a theoretical Marcus–Hush equation to understand the higher intermolecular coupling, resulting in easier carrier transports in pentacene molecules. In order to investigate the behavior of high-permittivity materials of BTO insulators in a logic circuit, simple and low-operating-voltage inverters are fabricated, and the gain is approximately 8.76 under a small operating voltage range from 0 to -5 V. [ABSTRACT FROM PUBLISHER]

Abstract: InGaP/InGaAs metal–oxide–semiconductor (MOS) pseudomorphic high-electron-mobility transistor (PHEMT) with a nanoscale liquid phase-oxidized InGaP as the gate dielectric is demonstrated. Not only does the MOS-PHEMT have the advantages of the MOS structure, but it also has high-carrier density and a high-mobility 2DEG channel. Using selective oxidation of InGaP by liquid phase oxidation, the MOS-PHEMT can be fabricated without additional recess processes. The MOS-PHEMT exhibits larger transconductance, lower gate leakage current, higher breakdown voltage, higher cut-off frequency, lower minimum noise figure, and higher power-added efficiency than does its counterpart (reference PHEMT). The interface roughness effect on the DC and RF performance of devices is also discussed. [Copyright &y& Elsevier]

Barium-doped \TiO2 films deposited on GaN layers at low temperature through a simple liquid phase deposition method is investigated. The use as a gate dielectric in AlGaN/GaN metal–oxide–semiconductor high-electron mobility transistors (MOSHEMTs) is also demonstrated. The electrical characteristics of the MOS structure on n-doped GaN show that the leakage current density is about \5.09 \times \10^-9\ \A/cm^2 at 1 MV/cm, and the breakdown field is more than 13 MV/cm. The maximum drain current density of the AlGaN/GaN MOSHEMTs is higher than that of HEMTs, in which a wider gate voltage swing and a lower subthreshold swing (110 mV/decade) are obtained. The gate leakage current density is significantly improved, and the gate pulse measurement shows that the current collapse is more suppressed for MOSHEMTs. [ABSTRACT FROM PUBLISHER]

• There is interaction between neutron and electron phenomenon. • Increase radiation time give longer interaction of neutron-electron. • Concentration of Ti3+ and V o increase by increasing the radiation time. • Defect development can be create by neutron beam treatment. • Orbital shifted toward nucleus phenomenon has been discovered. Influence of the interaction between neutron and TiO 2 surface is studied for the first time. By knowing the mechanism of this interaction, it could be useful to understand the possibility of the formation of Ti3+ and oxygen vacancy (V o) surface defect. Raman spectroscopy and X-ray Photoelectron Spectroscopy (XPS) were used for surface defect characterization analysis. According to XPS analysis, it shows that binding energy is shifted about 0.05 eV toward higher binding energy. The formation of Ti3+ and V o defect is depending on the irradiation time which explained that longer irradiation time would give more time to neutron-electron interaction, thus enhanced the defect development on TiO 2 thin film. [ABSTRACT FROM AUTHOR]