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In this study, we prepared a strontium ferrite titanate (STF) thin film using a sol–gel process to insulate resistive random-access memory (RRAM) applications. Compared to the typical strontium titanate (STO) RRAM, the improvement in the resistive switching characteristics in STF RRAM is obvious. The Al/STO/ITO/Glass RRAM set/reset voltages of −1.4 V/+3.3 V and the Al/STF/ITO/Glass RRAM set/reset voltages of −0.45 V/+1.55 V presented a memory window larger than 103, a low operating voltage and device stability of more than 104 s. In this study, the influence of Fe on the conducting paths and the bipolar resistive switching properties of Al/STF/ITO/Glass RRAM devices is investigated. [ABSTRACT FROM AUTHOR]

Activation energy, bipolar resistance switching behavior, and the electrical conduction transport properties of ITOX:SiO2 thin film resistive random access memory (RRAM) devices were observed and discussed. The ITOX:SiO2 thin films were prepared using a co-sputtering deposition method on the TiN/Si substrate. For the RRAM device structure fabrication, an Al/ITOX:SiO2/TiN/Si structure was prepared by using aluminum for the top electrode and a TiN material for the bottom electrode. In addition, grain growth, defect reduction, and RRAM device performance of the ITOX:SiO2 thin film for the various oxygen gas flow conditions were observed and described. Based on the I-V curve measurements of the RRAM devices, the turn on-off ratio and the bipolar resistance switching properties of the Al/ITOX:SiO2/TiN/Si RRAM devices in the set and reset states were also obtained. At low operating voltages and high resistance values, the conductance mechanism exhibits hopping conduction mechanisms for set states. Moreover, at high operating voltages, the conductance mechanism behaves as an ohmic conduction current mechanism. Finally, the Al/ITOX:SiO2/TiN/Si RRAM devices demonstrated memory window properties, bipolar resistance switching behavior, and nonvolatile characteristics for next-generation nonvolatile memory applications. [ABSTRACT FROM AUTHOR]

Using two kinds of targets (gallium and silicon dioxide) and the rf magnetron sputtering deposited technique, GdOx:SiO2 thin film RRAM devices were deposited on TiN/Si substrate to form a metal–insulator–metal (MIM) structure. In addition, different oxygen concentrations and rf sputtering power parameters were prepared for the GdOx:SiO2 thin films. Decrease of the defects and oxygen vacancies of the GdOx:SiO2 thin films were used and repaired by rapid thermal annealing technology. Indium tin oxide (ITO) as the top electrode on the GdOx:SiO2 thin film was prepared by the physical vapor deposition (PVD) method, and ITO/GdOx:SiO2/TiN/Si structures of the GdOx:SiO2 thin films' RRAM devices were also made. In addition, the current–voltage curves and devices' endurance properties were measured by an impedance analyzer. Finally, the crystalline style, the preferred phase, the grain size, and surface microstructure of the thin films were analyzed and observed from X-ray diffraction and field emission scanning electron microscope measurements. [ABSTRACT FROM AUTHOR]

In the reset state, the decay reaction mechanism and bipolar switching properties of vanadium oxide thin film RRAM devices for LRS/HRS are investigated and discussed here. To discover the properties of I-V switching curves, the first order rate law behaviors of the reset state between the resistant variety properties and the reaction time were observed. To verify the decay reaction mechanism in the reset state, vanadium oxide thin films from RRAM devices were measured by different constant voltage sampling and exhibited the same decay reaction rate constant. Finally, the electrical conduction transfer mechanism and metallic filament forming model described by I-V switching properties of the RRAM devices were proven and investigated. [ABSTRACT FROM AUTHOR]

In this study, a composite perovskite film composed of lead cesium triiodide (CsPbI3) quantum dots (QDs) and methylammonium lead iodide (CH3NH3PbI3; MAPbI3) was proposed. The CsPbI3 QDs prepared by hot-injecting were used as an anti-solvent in precursors to passivate the surface of this composite perovskite film. The further argon (Ar) plasma treatment improves the surface of the film. The effects of the powers from 100 to 200 W on the composite perovskite film structure, chemical element composition, and optical properties were studied. The experimental results demonstrate that the CsPbI3 QDs passivation boosts the ultraviolet light absorption (350–450 nm) and inhibits the formation of the PbI2 phase. Furthermore, Ar plasma treatment effectively improved CsPbI3 QDs passivation on MAPbI3 film. The powers lower than 140 W cause C=O bonds to dissolve and coordination bonds to form between OA carboxyl moieties and undercoordinated Pb2+ ions. At 160 and 140 W, the obvious crystal phase segregation and a decrease in light absorption are observed, respectively. Meanwhile, the strong bombardment of Ar ions at higher than 160 W causes the severe degradation of MAPbI3 film. [ABSTRACT FROM AUTHOR]

This article demonstrates changes in the structures of poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS) with the addition of organic additives. The mechanisms of PEDOT: PSS are analyzed using X-ray photoelectron spectroscopy (XPS), cross-sectional images obtained from scanning electron microscopy (SEM), and contact angles. In this paper, a bond-breaking reaction and phase separation are successfully found to occur between PEDOT: PSS molecules and the organic additives. Our research also finds that this bond-breaking reaction and phase separation exist in the PEDOT: PSS–sorbitol–maltitol film at the same time. The addition of organic additives will improve the optical properties and the moisture stability of PEDOT: PSS films. [ABSTRACT FROM AUTHOR]

In this study, the inorganic perovskite cesium lead triiodide (CsPbI3) quantum dots (QDs) produced by hot-injection method were added into the hybrid perovskite methylamine lead triiodide (CH3NH3PbI3; MAPbI3) to form composite perovskite film. It is not easy for argon (Ar) to react with perovskite. Therefore, argon plasma was used to optimize the properties of the surface. However, methylamine lead triiodide molecular will be degraded by excessive wattage. Therefore, the influence of plasma power acting on composite perovskite film was investigated. The experimental results show that the light absorption capacity can be increased by argon plasma power of 140 watt (W) acting on the surface of films because organic impurities are removed and surface morphology of film is changed. [ABSTRACT FROM AUTHOR]

This article demonstrates the change of structural and optical properties of poly (3,4-ethylene dioxythiophene): polystyrene sulfonate (PEDOT: PSS) by organic additive and acid treatment. The addition of sorbitol and maltitol can disperse the micelles of PEDOT: PSS. The mechanism of the bond-breaking reaction was investigated and a model for the bond-breaking reaction is also proposed. Furthermore, multiple formic acid treatments were found to reduce the PSS content of PEDOT: PSS, resulting in an enhancement in conductivity (4.2 × 104 S/m). [ABSTRACT FROM AUTHOR]

This study revealed the band gap, visible transmittance, and crystallinity variation Cd 1 − x S:B emitter layer at different boron concentrations, as well as the CuInSe 2 absorption layer nucleation mechanism at pH values ranging from 1.53 to 2.13. CuInSe 2 deposited at a pH of 1.73 showed the highest grain size (24.29 nm) and approached the stoichiometric state of [Cu]/[In] = 0.98, which produced was used for solar cells and Schottky diode. The conversion efficiency of Al/AZO/Cd 1 − x S:B/CuInSe 2 /Mo/Glass structure cell was 2.37% (V oc : 293 mV, J sc : 26.85 mA/cm 2 , and FF: 0.301). Moreover, the aluminum material were deposited on CuInSe 2 as a Schottky diode (Al/CuInSe 2 /Mo/Glass), which diode was used to estimate the work function (Φ) and ideality factor (n) through Schottky barrier. These device parameters of Al/CuInSe 2 structure was Φ CuInSe2 = 4.791 eV and n = 3.52, respectively. This result revealed that the Cd 1 − x S:B/CuInSe 2 interface state can cause Fermi-level pinning with an interface recombination velocity of 2.328 × 10 3 cm s − 1 . This indicates the poor performance of Schottky diodes and thin film solar cells comprising Cd 1 − x S:B/CuInSe 2 . However, experimental results demonstrated that the passivation of the surface by using iodine treatment can improve the Fermi-level pinning effect on Cd 1 − x S:B/CuInSe 2 interfaces. [ABSTRACT FROM AUTHOR]

This study investigates the effects of sputtering power on the performance of p-NiO:Li/n-Si heterojunction solar cells (HJSCs). The results of this study indicate a strong dependence of the cell characteristics on the sputtering power. Extremely high or low sputtering power generates higher interface state density ( D), resulting in the lowering of open circuit voltage ( V) and fill factor ( FF). The cell fabricated at a sputtering power of 100 W has the lowest D of 7.08 × 10 cm eV, corresponding to the highest conversion efficiency ( η) of 4.30 % [short circuit current density ( J): 18.06 mA cm, V: 390 mV, FF: 61.1 %, series resistance ( R): 4.3 Ωcm and shunt resistance ( R): 478.75 Ωcm]. Furthermore, the cell exhibits a considerably poor temperature coefficient of −0.70 %/ °C ( J: +0.07 %/°C, V: −0.52 %/°C and FF: −0.29 %/°C) when compared with conventional solar cells. Further improvement in the D of the cell is highly imperative for developing p-NiO:Li/n-Si HJSCs with a high conversion efficiency and a good temperature coefficient. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study is to reduce textured crystalline silicon (TCS) substrate surface-reflectivity over a wide spectral range (300–1100nm), to improve the step coverage of the textured structure, and to shift the minimal value of reflection from the unabsorbed region to the absorbed region. The TCS solar-cell interface between air and silicon was added to a SiO x /SiO x N y /SiN x triple-layer anti-reflective coatings (TLARCs) structure using the plasma-enhanced chemical vapor deposition (PECVD) growth method. This paper presents theoretical and practical discussions, as well as the experimental results of fabricating the films and devices. The average reflection of the SiO x /SiO x N y /SiN x TLARs reduced to 2.01% (300–1100nm). The minimal value of reflection was shifted from 1370nm (unabsorbed region) to 968nm (absorbed region). The SEM images show effective step coverage. In comparison to the untreated TCS solar cells, applying the experimental SiO x /SiO x N y /SiN x TLARCs to conventional TCS solar cells improved the short-circuit current density (J sc ) by 7.78%, and solar-cell efficiency by 10.95%. This study demonstrates that the SiO x /SiO x N y /SiN x TLARCs structure provides antireflective properties over a broad range of visible and near-infrared light wavelengths. An effective step coverage and minimal value of reflection from unabsorbed region shift to the absorbed region is demonstrated. [Copyright &y& Elsevier]

This study fabricates Al-Y codoped ZnO (AZOY)/n-Si heterojunction (HJ) solar cells using direct current magnetron sputtering and investigates the effect of etching time (from 30 to 120 s) on photovoltaic cell properties. To explore the effects of etching time on the optoelectrical properties of AZOY thin films, the films are deposited on glass substrate and then measured using a field-emission scanning electron microscope, atomic force microscopy, Hall effect measurement, and an ultraviolet-visible spectrometer. The results show that the resistivity, surface root mean square roughness, plasma resonance wavelength (\lambda\bf p), and haze value of films increase with an increase in etching time. The highest conversion efficiency (\eta:8.10\pm 0.11\%) of a cell is achieved with postdeposition etching for 60 s because of the higher AZOY thin film \lambda\bf p and haze values. The higher short circuit current density (J{\bf sc}) and open circuit voltage (V{\bf oc}) are proved again; low-cost and high-quality AZOY transparent conducting film is a good window layer for transparent conducting oxide/n-Si HJ solar cells. [ABSTRACT FROM PUBLISHER]

Low cost Al-Y codoped ZnO (AZOY) transparent conducting oxide (TCO) thin films were first deposited on glass substrate by DC magnetron sputtering technique as a anode for organic light emitting diode (OLED) application. Effects of two growth parameters (working pressure (PAr) and substrate temperature (Ts)) on the structural, electrical and optical properties of AZOY films have been investigated. The results showed that OLED devices fabricated with them exhibited slightly lower brightness approximately 3280 cd/m2 and slightly higher turn-on voltage (Von) approximately 2.6 V, than those fabricated with a conventional tin doped indium oxide anode approximately 3810 cd/m2 and approximately 2.4 V. Despite the poorer characteristics were observed in our device, we suggest that optoelectrical properties of AZOY thin films can be improved further in the future study. In summary, AZOY transparent conducting thin film deposited by DC magnetron sputtering is a promising anode for low cost and high efficiency OLED application. [ABSTRACT FROM PUBLISHER]

In this study, we describe composited perovskite films based on the doping of lead cesium triiodide (CsPbI3) quantum dots (QDs) into methylammonium lead iodide (MAPbI3). CsPbI3 QDs and MAPbI3 were prepared by ligand-assisted re-precipitation and solution mixing, respectively. These films were optimized by oxygen plasma treatment, and the effect of powers from 0 to 80 W on the structural properties of the composited perovskite films is discussed. The experimental results showed that the light-harvesting ability of the films was enhanced at 20 W. The formation of the metastable state (lead(II) oxide and lead tetroxide) was demonstrated by peak differentiation-imitating. A low power enhanced the quality of the films due to the removal of organic impurities, whereas a high power caused surface damage in the films owing to the severe degradation of MAPbI3. [ABSTRACT FROM AUTHOR]

In this study, a simple hot-injection method to synthesize high-quality inorganic perovskite cesium lead iodide (CsPbI3) quantum-dots (QDs) was demonstrated. Adding CsPbI3 QDs into the organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a composite perovskite film, annealed by different temperatures, was found to be effectively enhanced by the perovskite crystallization. The intensity of the preferred peak (110) of MAPbI3 was enhanced by increasing the size of the crystal and reducing the cluster crystal. The densest film can be found at annealing temperature of 140 °C. The full width half maximum of MAPbI3 and CsPbI3 was analyzed through XRD peak fitting. This was a huge breakthrough for QDs doped perovskite films. [ABSTRACT FROM AUTHOR]

Abstract: Fluorine-doped ZnO transparent conductive thin films were successfully deposited on glass substrate by radio frequency magnetron sputtering of ZnF2. The effects of rapid thermal annealing in vacuum on the optical and electrical properties of fluorine-doped ZnO thin films have been investigated. X-ray diffraction spectra indicate that no fluorine compounds, such as ZnF2, except ZnO were observed. The specimen annealed at 500 °C has the lowest resistivity of 6.65×10−4 Ω cm, the highest carrier concentration of 1.95×1021 cm−3, and the highest energy band gap of 3.46 eV. The average transmittance in the visible region of the F-doped ZnO thin films as-deposited and annealed is over 90%. [Copyright &y& Elsevier]

The effect of conventional Perovskite solar cells (PSCs) by using different concentration and spin-coating speeds of titanium dioxide (TiO2) as an electron transport layer (ETL) was studied. The influence of TiO2 based on device structure: fluorine-doped tin oxide substrate/TiO2/Perovskite (CH3NH3PbI3)/2,2′,7,7′-Tetrakis[N,N-di(4-methoxyp phenyl)amino]-9,9′-spirobifluorene/silver, is also studied. The spin-coating speed is varied in a range from 1000 to 3000 rpm to get optimal performance of device. The optimized power conversion efficiency (PCE) of PSCs with original concentration (OC) and double concentration (DC) TiO2 is 8.74 and 9.93%, respectively. The reason is attributed to excellent absorption in shorter wavelength, compact characteristic, and suitable thickness of TiO2, leading to perfect short-circuit current density (Jsc), lower series resistance (Rs), and higher fill factor (FF) of 0.75. Besides, recombination of electron and hole is also decreased due to the compact feature, leading to higher open-circuit voltage (VOC) of 0.91 V. [ABSTRACT FROM AUTHOR]

Using an advanced ultraviolet irradiation (UV curing) process, a high performance porous low-k film of k=2.57, whose Young's modulus is larger than 8 GPa, now is developed to improve the mechanical properties of a film by the reconstruction of Si–O network structure from cage-like Si–O bonds, suboxide structures and Si–CH3 bonds. It was found that the UV curing process can efficiently strengthen the mechanical properties of porous low-k film, and reduce its dielectric constant value by removing hydrocarbon bonds to form porosities. As a result, the key features of this optimal SiOCH material, high elastic modulus and a low dielectric constant, provide promising properties for future integrated schemes. [ABSTRACT FROM AUTHOR]

The generation of oxide charges and interface states during the program/erase operation in flash memory has been known to degrade the tunnel oxide quality. However, there is still no effective method to analyse the endurance and disturbed performance of the flash memory at the test level. So in this paper, a simple and fast method is applied to characterize the endurance and disturbed performance on a 98K bit flash cell array stress test structure. Based on this structure, the behaviour of the weakest part of the memory array after the program/erase operation can be easily observed. Moreover, the effects of the oxide charges and interface states generated are also discussed. Also, excess hole trapping in the oxide leads to fast charge loss during the disturbance test. The fast charge loss caused by holes is the more serious of these two failure mechanisms because the relatively low high-state VT can be corrected by circuit-level, program/erase-verified sequences. However, poor disturbance characteristics cause logical errors during the reading of an array. [ABSTRACT FROM AUTHOR]

We report a metal-insulator-semiconductor (MIS) diode with an α-Ga 2 O 3 thin-film insulator layer grown by liquid-phase deposition (LPD). α-Ga 2 O 3 exhibits a high energy bandgap of 4.9–5.3 eV, which can effectively reduce the leakage current density and improve the breakdown voltage of the diode. The α-Ga 2 O 3 thin films are synthesized from GaOOH with LPD. The α-GaOOH crystal is simply obtained by the dissociation of the Ga(OH) 3 precursor solution. GaOOH can be transformed into α-Ga 2 O 3 crystal and form a uniform thin film following post-growth annealing. When the α-Ga 2 O 3 thin film is inserted in between Ni and Si to form a Ni/α-Ga 2 O 3 /Si MIS diode, the barrier height of the diode increases by 0.4 eV and the on/off ratio by 100-fold from those of the Ni/Si Schottky diode. The Ni/α-Ga 2 O 3 /Si MIS diode exhibits a leakage current density of 1.07 × 10−5A/cm2 under −2 V bias. The breakdown voltage of the diode reaches −166 V without the guard ring and other insulation structures. Our results demonstrate that LPD-grown α-Ga 2 O 3 thin films can obtain uniform and dense structure under short deposition time and at an annealing temperature of 400 °C. The uniform insulating layer of α-Ga 2 O 3 has a high potential in enhancing the electrical characteristic of diodes and other power electronic devices. • α-Ga 2 O 3 thin films were synthesized by liquid phase deposition with annealing. • α-Ga 2 O 3 thin films are uniform and dense. • Ni/α-Ga 2 O 3 /Si diode exhibits a current density of 1.07 × 10−5 A/cm2 at −2 V. [ABSTRACT FROM AUTHOR]

Abstract: In this study, Anodic Aluminum Oxide (AAO) is used as the storage layer instead of silicon nitride in a silicon–SiO2–Si3N4–SiO2–Silcon (SONOS) structure in flash memory devices and a double I–V method is utilized to investigate its charge trapping behavior on SiO2–Al2O3–SiO2 (OAO) triple stacks. The experimental results show that more initial charge density can be charged into the centroids of neutral charge trapping sites using post deposition annealing (PDA) treatment in OAO triple stacks. Under stress bias testing, OAO triple stacks exhibit a larger shift of threshold voltage than do ONO type devices. The trap energy levels of the bulk electron traps in high k AAO materials were determined. The initial trapping charges are produced during the fabrication process and are changed into centroids of neutral charge trapping sites after PDA treatment, which are responsible for charge trapping/de-trapping during programming/erasing. All devices show that the trapping centroid moves to the top oxide with an increase of stress time. [Copyright &y& Elsevier]