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Flexible organic field-effect transistor nonvolatile memories (OFET-NVMs) with polymer electrets have aroused great attention for its important role in next-generation flexible data storage devices application. However, the OFET-NVMs to date still hardly reach the requirements for practical applications. In air environment, the positively charged defects formed in pentacene near the interface with polymer, result in unsatisfied high programming/erasing (P/E) voltages. Here, we propose an OFET memory structure, in which an n-type semiconductor N, N′-Bis(3-pentyl) perylene-3, 4, 9, 10-bis(dicarboximide) (PTCDI-C13) is inserted between pentacene and poly(4-vinyl phenol. Based on the electrostatic induction effect, electrons are induced on the surface of PTCDI-C13 due to the electrostatic field generated by the positive charges at the interface of pentacene/polymer, and compensate part of the positive charges at the interface, resulting in the reduction of the height of hole-barrier. The flexible memory device with PTCDI-C13 exhibits a memory window of larger than 7 V at P/E voltages (±20 V), fast switching speeds (0.5 ms), good P/E endurance (>400 cycles), large field-effect mobility (0.026 cm2 V−1 s−1), and long retention time (over 104 s).

Because the setting method of back pressure of direct air cooling system is not reasonable, the fluctuation range of back pressure and load change are larger when the unit is peak shaving, which reduces the economic efficiency of the unit. In this paper, based on the optimal back pressure of field data calculation, particle swarm optimization (PSO) is used to optimize the modeling of BP neural network. The results show that, compared with the conventional BP model, the back pressure setting value predicted by the optimized model is more accurate, the model precision is higher, and it is more suitable for industrial field application. This method also provides some reference for the modeling of other objects in the process of thermal production.

With the comprehensive promotion of the ultra-low emission and energy-saving renovation plans for coal-fired power plants, for the complexity of the combined SO2 removal system inside and outside the furnace of CFB units, the traditional identification method has the problems of slow convergence and low identification accuracy. Taking the combined desulfurization system inside and outside the furnace of a 300MW CFB unit of a meteorite power plant as the research object, using the actual operating data of the production system, the particle swarm optimization(PSO) algorithm based on adaptive weight is designed to establish the mathematical model of the desulfurization system inside and outside the furnace, which has reference value for energy saving and optimization of automatic control strategy in the combined desulfurization system

A memory device has been fabricated using an AgI film sandwiched between a Pt film and an Ag film with the lateral size of the device scaled down to 300 nm. The AgI film was made by the iodination of the Ag film at room temperature and under ambient pressure. The switching between high- and low-resistance states can be realized by applying voltages of different polarities. The switching can be performed under the application of voltage pulses with a 100 Hz frequency for ~103 times. The switching times are in the order of microseconds and the retention time is about a week. The switching effects are explained as the electrochemical growth and dissolution of Ag in AgI.

Poly-methy1-methacrylate (PMMA) films were prepared by pulsed laser deposition on a Si (1 0 0) substrate at different temperatures. The films were characterized by using Fourier transform infrared spectrum, x-ray photoelectron spectroscopy, scanning electron microscope (SEM) and atomic force microscope. It was observed that the molecular structure of the PMMA films transformed from isotactic to syndiotactic during ablation and subsequent deposition. However, the deposition process does not significantly alter the monomer composition of the polymer films, as compared with the PMMA target. The substrate temperature shows great effects on the surface morphology and the leakage current of the PMMA films. It is expected that the PMMA films with flat surface and optimum chemical stability might provide some applications in a microelectronic device.

We have proposed a novel memory device with the Cu/CuI0.76S0.14/Pt structure. The intermediate non-stoichiometric film is prepared by pulsed laser deposition. This compound is found with the zincblende structure at room temperature by using x-ray diffraction. Conductance?voltage characteristics reveal that a switching effect exists when the polarity of the voltage biased is changed. By applying a voltage of +0.5?V on the copper electrode, our device is switched on while ?0.8?V induces the OFF-state. The switching operation could be repeated at least 103 times, and the GON/GOFF ratio is more than 3 ? 103. It is expected to be a promising model of nonvolatile memories. With the TEM study, we have analysed the migration of Cu+, S2? and I? under an electric field and attribute the switching effect to the formation and annihilation of ionic conducting paths.

In color superconductor the gluon condensate drops down at moderate density but goes up at high density and can even exceed its vacuum value when the density is high enough.

Highly 111 oriented Pb(Ta0.05 Zr0.48 Ti0.47 )O3 (PTZT) ferroelectric thin films were deposited on Pt/TiO2 /SiO2 /Si substrates using a La0.67 Sr0.33 MnO3 (LSMO) buffer layer. It is found that the LSMO buffer layers induced highly (111) textured growth of PTZT films. Ferroelectric hysteresis measurements showed that the remnant polarization and coercive field of these films are about 20 µC cm-2 and 20 kV cm-1 , respectively. After 1 × 1011 switching cycles at 5 V (about 100 kV cm-1 applied field) in fatigue tests, the decay of non-volatile polarization of these films was only about 6% of the initial value. No significant degradation of the polarization can be found in these films over a waiting time of 1 × 105 s in the retain test. It is proposed that the high degree of 111 orientation of the PTZT films induced by LSMO is responsible for the excellent performance of the PTZT film capacitors. These studies demonstrated that the PTZT films with the LSMO buffer layer look very promising for ferroelectric memory applications and the developed techniques are very compatible with semiconductor technology.

The roles of moisture in resistive switching (RS) devices are closely related to the RS mechanism. In principle, the nonpolar RS promises symmetric behaviors independent of the polarities of operating voltages. However, the effect of humidity on the RS characteristics of Pt/TiO2− x /Pt nonpolar cells is confirmed to be polarity-dependent. The positive electroforming threshold voltage decreases when humidity increases, whereas the negative one is unaffected. This asymmetric phenomenon can be attributed to the polarity-associated rule of current varying with humidity before electroforming. The voltage distribution in the device and then the electroforming threshold voltage are modified.

We report polarization-controlled tunable rectifying behaviors in (K,Na)NbO3 (KNN)/LaNiO3 (LNO) heterostructures on silicon. The heterostructure shows a forward diode behavior at both the high resistance state and the low resistance state. The amplitude dependent rectifying features are attributed to the ferroelectric modulation effect on both the width of the depletion region and the height of the potential barrier at the KNN/LNO interface. By controlling the domain configurations using the writing voltage, the rectifying behaviors can be regulated and immediate states can be tuned. Our work shows the potential applications of KNN films in ferroelectric memristors.

On the basis of the density functional theory coupled with the Boltzmann transport equation with relaxation time approximation, we investigate the electronic structure and predict the electron mobility of few-layer InSe. Few-layer InSe has a tunable band gap on thickness. At the same time, it possesses a high carrier mobility on the order of 103 cm2 V−1 s−1. As we demonstrated, few-layer InSe has potential applications for next-generation electronic materials owing to its considerable band gap and high carrier mobility.

H2 production has been predicted in some metal–insulator–metal resistive switching devices and similar structures, but experimentally has not yet been reported. Here we discovered cathode bubbles in Pt/TiO2−x /Pt unipolar resistive switching cells when electroforming is implemented in a humid environment. But then these bubbles are absent when cells are operated in an anhydrous environment. The focused ion beam technique was used to observe the deformation of the cell induced by bubbles. These bubbles are deduced to be filled with H2 generated at the cathode by the reduction of protons from adsorbed water. Reduced oxides containing abundant oxygen vacancies facilitate the dissociation of adsorbed water and supply sufficient protons diffusing towards the cathode.

The fully transparent indium—tin-oxide/BaSnO3/F-doped SnO2 devices that show a stable bipolar resistance switching effect are successfully fabricated. In addition to the transmittance being above 87% for visible light, an initial forming process is unnecessary for the production of transparent memory. Fittings to the current—voltage curves reveal the interfacial conduction in the devices. The first-principles calculation indicates that the oxygen vacancies in cubic BaSnO3 will form the defective energy level below the bottom of conduction band. The field-induced resistance change can be explained based on the change of the interfacial Schottky barrier, due to the migration of oxygen vacancies in the vicinity of the interface. This work presents a candidate material BaSnO3 for the application of resistive random access memory to transparent electronics.

The charge-trapping memory devices with the structures p-Si/Al2O3/AlTi4Ox/Al2O3/Pt were fabricated by using atomic layer deposition and RF magnetron sputtering techniques, and a memory window of 6.61 V and a high charge-trapping density of 1.29 × 1013 cm−2 at gate voltage of ±11 V have been obtained. The remarkable charge-trapping effect in the high-k composite oxide layer was ascribed to the electron-occupied defect states formed by the inter-diffusion at the interface of TiO2/Al2O3. An Al2O3 layer intercalated in the charge-trapping layer AlTi4Ox enlarged the memory window to 14.59 V and also improved the data retention property by suppressing the vertical charge migration.

Sb2Te films with different Ti contents (TixSb2Te) are derived via the target-attachment method by using the magnetron sputtering technique. The effects of the Ti content on the phase change characteristics and the microstructures are investigated by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy and atom force microcopy. Resistance-temperature measurements are carried out to reveal the enhanced crystallization temperature of TixSb2Te films, indicating a better thermal stability in such films. Both the activation energy and the temperature for 10 y data retention increase with increasing the concentration of Ti. It indicates that the crystallization of the amorphous Sb2Te film could be suppressed by the introduction of Ti. The improvement of crystallization temperature and the thermal stability of the amorphous Sb2Te film results from the introduction of Ti in Sb-Te bond that decreases the binding energy of Sb 4d and Te 4d.

A memory device Si/Al2O3/Al2O3-Cu2O/Al2O3/Pt is fabricated by using atomic layer deposition and rf-magnetron sputtering techniques. The memory device including the composite of Al2O3 and Cu2O as the charge storage layer shows a distinguished charge trapping capability. At a working voltage of ±11 V a memory window of 9.22 V is obtained. The x-ray photoelectron spectroscopic study shows a shoulder from Cu2+ ions around the peak of Cu1+ ions. It is suggested that the charge-trapping mechanism should be attributed to the defect states formed by the inter-diffusion at the interface of two oxides.

Fully transparent indium–tin-oxide/high-k-rare-earth-oxide Eu2O3/F-doped SnO2 devices that show stable bipolar resistance switching have been successfully fabricated. In addition to the transmittance of above 86% for visible light, high resistance ratio, good data retention and initial forming-free resistance switching behaviour were obtained in the transparent memory. The results of high-resolution spectroscopy and x-ray photoelectron spectroscopy analyses combining with the temperature dependence of resistance suggest that metallic Eu filaments are formed in the low-resistance state. Mechanism analysis indicates that the coexistence of oxygen vacancies and metallic Eu in the Eu2O3 films plays an important role in the forming-free resistive switching performance. The switching mechanism was attributed to formation/oxidation of filamentary and oxygen ion migration.

A composition-modulated (HfO2)x(Al2O3)1−x charge trapping layer is proposed for charge trap flash memory by controlling the Al atom content to form a peak and valley shaped band gap. It is found that the memory device using the composition-modulated (HfO2)x(Al2O3)1−x as the charge trapping layer exhibits a larger memory window of 11.5 V, improves data retention even at high temperature, and enhances the program/erase speed. Improvements of the memory characteristics are attributed to the special band-gap structure resulting from the composition-modulated trapping layer. Therefore, the composition-modulated charge trapping layer may be useful in future nonvolatile flash memory device application.

ZrO2 nanocrystallite-based charge trap flash memory capacitors incorporating a (ZrO2)0.6(SiO2)0.4 pseudobinary high-k oxide film as the charge trapping layer were prepared and investigated. The precipitation reaction in the charge trapping layer, forming ZrO2 nanocrystallites during rapid thermal annealing, was investigated by transmission electron microscopy and X-ray diffraction. It was observed that a ZrO2 nanocrystallite-based memory capacitor after post-annealing at 850 ?C for 60 s exhibits a maximum memory window of about 6.8 V, good endurance and a low charge loss of ~25% over a period of 10 years (determined by extrapolating the charge loss curve measured experimentally), even at 85 ?C. Such 850 ?C-annealed memory capacitors appear to be candidates for future nonvolatile flash memory device applications.

GeTe4 films are deposited by using a dc magnetron sputtering technique, and its structural, thermal and electrical properties are investigated systematically. The prototypical phase-change memory cells are fabricated by using a focused ion beam and magnetron sputtering techniques. Compared with Ge2Sb2Te5, the GeTe4 film exhibits a higher crystallization temperature (235°C), better data retention of ten years at 129°C, and larger activation energy (2.94 eV). GeTe4 phase change memory cells with an effective diameter of 1 μm show proper switching speed, low power consumption, and good resistance contrast. The Set and Reset operations are achieved by using a 200-ns 2.0-V pulse and a 30-ns 3.0-V pulse, respectively. The dynamic switching ratio between the OFF and ON states is larger than 1 × 104.

The formation and diffusion of vacancies are studied in LaAlO3/SrTiO3 heterostructures. Oxygen vacancies (V OS) appear easily in the SrTiO3 substrate during LaAlO3 film growth at 700 °C and 10−4 Pa oxygen pressure rather than at 10−3–10−1 Pa, thus the latter two-dimensional electron gas should come from the polarity discontinuity at the (LaO)+/(TiO2)0 interface. For SrTiO3−δ /LaAlO3/SrTiO3, high-density V OS of the SrTiO3−δ film can pass through the LaAlO3 film and then diffuse to 1.7 µm depth in the SrTiO3 substrate, suggesting that LaAlO3 has V OS at its middle-deep energy levels within the band gap. Moreover, high-density V OS may combine with a strontium/titanium vacancy (V Sr/Ti) to form V Sr/Ti–O complexes in the SrTiO3 substrate at 700 °C.

The synthesis of ZnO architecture on a fluorine-doped SnO2 (FTO) conducting glass pre-coated with nanoporous TiO2 film has been achieved by a one-step hydrothermal method at a temperature of 70°C. The effect of the reaction time on the morphology of the ZnO architecture has been investigated, and a possible growth mechanism for the formation of the ZnO architecture is discussed in detail. The morphology and phase structures of the as-obtained composite films have been investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results show that the growth time greatly affects the morphology of the obtained ZnO architecture. The photoelectrochemical performances of as-prepared composite films are measured by assembling them into dye sensitized solar cells (DSSCs). The DSSC based on the as-prepared composite film (2 h) has obtained the best power conversion efficiency of 1.845%.

GaN/Pb(Zr0.53Ti0.47)O3 structures have been fabricated by light radiation heating low-pressure metal-organic chemical deposition and pulsed laser deposition. These structures show leakage current lower than 10-11 A at applied voltage of 5 V. X-ray diffraction shows that ferroelectric Pb(Zr0.53Ti0.47)O3 films directly on GaN are well crystallized with perovskite structure. Because of the high thermal stability and relatively smaller mismatch between GaN and ferroelectrics in comparison with that of Si/ferroelectric structures, GaN looks like more promising as semiconductor active layer for metal-ferroelectric-semiconductor field effect transistors.

RbAg4I5 solid electrolyte films have been prepared using the pulsed laser deposition technique. Their structures have been characterized by x-ray diffraction, and the surface and cross-section morphologies have been investigated by using scanning electron microscopy. It was found that larger energy density of the laser beam favoured the crystallization of RbAg4I5 particles and increased the resistance of the 'off' state, and lower energy density of the laser beam induces the appearance of the AgI phase in the films and reduces the resistance of the 'off' state. A narrow 'window' of the substrate temperature (around 80 °C) for the deposition of pure RbAg4I5 films has also been observed. The RbAg4I5 film deposited on Pt/TiO2/SiO2/Si(1 1 1) substrates at 80 °C shows a uniform and flat surface. All the RbAg4I5 memory devices show obvious resistive switching behaviour.