Search

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 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]

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 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]

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]