SYNTHESIS, STRUCTURE AND ELECTRICAL PROPERTIES OF POLY(PHENYLENE VINYLENE) FILM DOPED WITH FERRIC CHLORIDE

Poly(phenylene vinylene) (PPV) him was synthesized via a soluble precursor polymer. Strong fluorescence at 500-600 nm was observed in both precursor and PPV him. Room-temperature conductivity of PPV him doped with FeCl3 depends on the elimination temperature, the concentration of FeCl3 and doping time. The maximum conductivity of doped PPV at room-temperature can reach about 40 S . cm(-1). The temperature dependence of conductivity was controlled by 1D-VRH (1 Dimension Variable Range Hopping) model with T-0 value of 3.9 x 10(3) K. Non-Ohmic conductivity resulting from Schottky effect was observed and the value of converted voltage from Ohmic region into non-Ohmic region at the current-voltage characteristic was found to be dependent upon the work function of electrodes.

Investigation on the Trap Signature in Organic Semiconductor Turmeric Film Through Current-Voltage Analysis

The analytical description of the trap signature in the charge conduction process of turmeric dye-based organic semiconductor has been presented in this study.An analytical explanation of the built-in potential Ⅴx-Ⅴ graph that emphasizes the presence of trapping states has been provided.Differential analysis of current-voltage(Ⅰ-Ⅴ)characteristics has also been conducted to verify the trap signature of the carrier in the device.The non-monotonous decrement of the G(Ⅴ)-Ⅴ plot verifies the trap signature.The values of trap energy(Et)and trap factor(θ)have been derived from the logarithmic Ⅰ-Ⅴ relationship.From the analysis of the semilogarithmic Ⅰ-Ⅴ plot,the barrier height(ϕbi)of the device has also been determined.The overallⅠ-Ⅴcurve has been taken into account to examine the Richardson-Schottky and Poole-Frenkel effects on the trap-assisted charge conduction process.From the results of the experiment,the Schottky effect has been observed to be effective,which leads to a bulk-limited charge conduction process.

The enhanced performance of piezoelectric nanogenerator via suppressing screening effect with Au particles/ZnO nanoarrays Schottky junction

This paper describes a novel strategy to weaken the piezopotential screening effect by forming Schottky junctions on the ZnO surface through the introduction of Au particles onto the surface. With this approach, the piezoelectric-energyconversion performance was greatly enhanced. The output voltage and current density of the Au@ZnO nanoarray-based piezoelectric nanogenerator reached 2 V and 1 μA/cm^2, respectively, 10 times higher than the output of pristine ZnO nanoarray-based piezoelectric nanogenerators. We attribute this enhancement to dramatic suppression of the screening effect due to the decreased carrier concentration, as determined by scanning Kelvin probe microscope measurements and impedance analysis. The lowered capacitance of the Au@ZnO nanoarraybased piezoelectric nanogenerator also contributes to the improved output. This work provides a novel method to enhance the performance of piezoelectric nanogenerators and possibly extends to piezotronics and piezophototronics.

Promoting selective electroreduction of nitrates to ammonia over electron-deficient Co modulated by rectifying Schottky contacts

Developing efficient electrocatalysts for selective nitrate contamination reduction into value-added ammonia is significant.Here,heterostructured Co/CoO nanosheet arrays(Co/CoO NSAs)exhibited excellent Faradaic efficiency(93.8%)and selectivity(91.2%)for nitrate electroreduction to ammonia,greatly outperforming Co NSAs.15N isotope labeling experiments and 1H nuclear magnetic resonance(NMR)quantitative testing methods confirmed the origin of the produced ammonia.Electrochemical in situ Fourier transform infrared(FTIR)spectroscopy,online differential electrochemical mass spectrometry(DEMS)data and density functional theory(DFT)results revealed that the superior performances arose from the electron deficiency of Co induced by the rectifying Schottky contact in the Co/CoO heterostructures.The electron transfer from Co to CoO at the interface could not only suppress the competitive hydrogen evolution reaction,but also increase energy barriers for by-products,thus leading to high Faradaic efficiency and selectivity of ammonia.

Electrical transport and current properties of rare-earth dysprosium Schottky electrode on p-type GaN at various annealing temperatures

The electrical and current transport properties of rapidly annealed Dy/p-GaN SBD are probed by I-V and C-V techniques. The estimated barrier heights（BH） of as-deposited and 200 ℃ annealed SBDs are 0.80 eV（I-V）/0.93 eV（C-V） and 0.87 eV（I-V）/1.03 eV（C-V）. However, the BH rises to 0.99 eV（I-V）/1.18 eV（C-V）and then slightly deceases to 0.92 eV（I-V）/1.03 eV（C-V） after annealing at 300 ℃ and 400 ℃. The utmost BH is attained after annealing at 300 ℃ and thus the optimum annealing for SBD is 300 ℃. By applying Cheung＇s functions, the series resistance of the SBD is estimated. The BHs estimated by I-V, Cheung＇s and ΨS-V plot are closely matched; hence the techniques used here are consistency and validity. The interface state density of the as-deposited and annealed contacts are calculated and we found that the NSS decreases up to 300 ℃ annealing and then slightly increases after annealing at 400 ℃. Analysis indicates that ohmic and space charge limited conduction mechanisms are found at low and higher voltages in forward-bias irrespective of annealing temperatures. Our experimental results demonstrate that the Poole-Frenkel emission is leading under the reverse bias of Dy/p-GaN SBD at all annealing temperatures.

SBH adjustment characteristic of the dopant segregation process for NiSi/n-Si SJDs

By means of analyzing theⅠ-Ⅴcharacteristic curve of NiSi/n-Si Schottkyjunction diodes（NiSi/n-Si SJDs）, abstracting the effective Schottky barrier height（φ_（B,eff）） and the idealfactor ofNiSi/n-Si SJDs and measuring the sheet resistance of NiSi films（R_（NiSi））,we study the effects of different dopant segregation process parameters,including impurity implantation dose,segregation annealing temperature and segregation annealing time,on theφ_（B,eff） of NiSi/ n-Si SJDs and the resistance characteristic of NiSi films.In addition,the changing rules ofφ_（B,eff） and R_（NiSi） are discussed.