Source Meter Research Articles

便携式光源、光功率计系统开发与设计

便携式光源、光功率计系统开发与设计

Improved broadband antireflection in MoO3/GaAs heterojunction

Large area surface micro-structuring is most commonly used to reduce the reflection loss and improve the light absorption in solar cells, photo-detectors and image sensors. Herein, chemically prepared textured GaAs with improved absorption in the entire range of the solar spectrum is investigated using UV–Vis–NIR spectrometer, showing that an average specular reflectance can be reduced to ~ 0.2% in the wavelength range of 3000–300 nm. The sputtered MoO3 thin film (10 nm) on textured GaAs further reduces the reflection loss down to ~ 0.1% (average value) in same wavelength range, i.e., 300–3000 nm. The phase, morphology, composition, and transport properties of the thin films were investigated using XRD, SEM, AFM, XPS, and Keithley source meter, respectively. SEM and AFM scanning show highly ordered elongated microstructure has been induced on pristine GaAs substrate after wet chemical etching. XRD analysis shows amorphous nature of the MoO3 thin film. In addition, XPS studies confirm that MoO3 thin film present on the surface of textured GaAs. Moreover, hole-blocking property of the MoO3 thin film has been studied with the help of Anderson model. Further, current–voltage characteristics (under dark condition) show rectifying behavior of the heterojunction (Ag/MoO3/GaAs/Ag). Hence, the present study is not only important for the basic understanding of charge transports across the heterojunction, but also to also to design hole-blocking-based solar cell.

Thermochromic Properties of Vanadium Oxide Films Prepared by R-HIPIMS Using Closed-Loop Controlled with Plasma Emission Monitoring

The vanadium dioxide films were deposited by reactive high-power impulse magnetron sputtering for different plasma emission intensity at the substrate temperature of 310 °C. The setpoint of plasma emission intensity was controlled by a PID controller with plasma-emission-monitoring. The vanadium dioxide films characteristics were measured by optical spectrophotometer, X-ray diffraction and electrical source meter.

Pulsed 70 kV X-ray sensing behavior of Cu2HgI4 thick films

X-ray photoconductors are widely used in flat panel X-ray detectors in medical and dental imaging systems. In the present work, X-ray photoconductivity measurement of Cu2HgI4 thick film was performed using a real-time intraoral X-ray machine. To perform the sensing measurement, wet chemical derived Cu2HgI4 sample was coated as a thick film by slurry deposition route on top of the tin coated copper patterned electrode. Prior to the sensing measurement, Cu2HgI4 powder sample was characterized using powder X-ray diffraction, scanning electron microscope, energy dispersive x-ray analysis, Fourier transformed infrared spectroscopy and diffused reflectance spectroscopy. These analysis confirms the sample is in single phase with crystallites are in sub-spherical morphologies. The resistance of Cu2HgI4 thick film was measured under the presence and absence of pulsed 70 kV X-ray for various exposure durations from 0.06 to 3.2 s using a Keithley 2450 source meter. Appreciable sensitivity against intraoral pulsed 70 kV X-ray sensing behavior of Cu2HgI4 thick films explore the possibility of utilizing it as a photoconductor for flat panel X-ray imaging detectors.

Mechanical and opto-electrical response of embedded smart composite coating produced via electrodeposition technique for embedded system in defence application

The emergence of nanocomposite particulate with the increasing demand for opto-electrical properties for defence application has necessitated this study. In this work, an attempt was made to develop Zn-CeO2/Zn-CeO2-Al2SiO5 thin film composite on A356 mild steel using electrodeposition technique. The developed coating was attained in 2 V for 10 min at a constant current density of 1.5 A/cm2 and pH of 4.5. The mass concentration of Al2SiO5 was varied, ranging from 0 to 15 g. The composite coatings were characterized using Scanning electron microscope equipped with energy dispersive spectrometer (SEM/EDS). The corroding properties of the coated and uncoated sample were examined through potentiodynamic polarization technique via Autolab PGSTAT 101 Metrohm potentiostat/galvanostat with NOVA software of version 2.1.2 in 3.65% NaCl. The electrical characterization was carried out using voltage-ammeter meter and Keithley 2400 series source meter application tester. The opto-electrical investigation was done using a solar simulator with maximum intensity of 1000 W/m2 under an air mass of 1.5 at a working intensity of 750 W/m2. The outcome of various test and characterizations revealed that the electrodeposited Zn-CeO2/Zn-CeO2-Al2SiO5 possessed good stability, improved microstructural qualities, better electrical conductivity and outstanding corrosion resistance.

Enhanced conduction in CdSe nanowires on 200 keV phosphorous negative ion implantation

For II–VI compound semiconductor nanostructures, ion implantation is considered to be an area of significant interest due to its potential use in the fabrication of the extensive variety of novel optoelectric devices. CdSe nanowires with diameter 80 nm have been grown via the template-assisted electro-deposition method and were subsequently implanted with 200 keV negative phosphorous ions at fluence ranging from 1011 ions/cm2 to 1013 ions/cm2. SRIM-TRIM simulation studies are done to understand the course and nature of events occurring during implantation. Pre- and post-implanted samples were characterized by Scanning electron microscope (SEM), X-Ray diffraction (XRD), UV–vis spectroscopy and Probe station with a Keithley source meter. Structural studies reveal no modification in crystal structure upon implantation. An increase of phosphorous content led to an apparent red shift in the optical band gap and an improvement in conductivity. These modifications are attributed to the ionization and the creation of damage on implantation.

Electrical Property of Anchored Chitosan/Silver on Reduced Graphene Oxide Aerogel

Silver (Ag)/chitosan (CHT) functionalized Reduced graphene oxide aerogel was fabricated. CHT/Ag decorated reduced graphene oxide aerogel (RGOA) was characterized using XRD, Raman spectroscopy, Fourier transformed infrared spectroscopy. Scanning electron microscopy were explaining the surface morphology of CHT/Ag/RGOA. Physical techniques such as, spectroscopy and microscopy spectrum confirms the noncovalent interaction between graphene oxide layers and also the electrostatic interaction between Ag and CHT, RGOA. Electrostatically interacted Ag and CHT could enhance the properties of RGOA. The DC electrical conductivity of the CHT/Ag wrapped RGOA investigated from I–V characteristics using keithly source meter. Thus, results indicate CHT/Ag/RGOA has enhanced electrical conductivity due to the influence of interacted silver particles.

Influence of NH4Cl treatment on physical properties of CdTe thin films for absorber layer applications

The physical properties of electron beam evaporated and chlorine-passivated CdTe thin films are investigated and the influence of NH4Cl treatment on these properties is studied. X-ray diffraction, UV–Vis spectrophotometry, energy-dispersive spectroscopy, atomic force microscopy, and a source meter were used to investigate the physical properties, which were optimized by varying the temperature of the treatment after NH4Cl activation. Structural analysis reveals that the crystallinity is increased at lower annealing temperature while a partial phase transition and oxidation are observed at higher annealing temperature. The absorbance is high in the visible region, and a red shift is observed at higher wavelength, while the direct bandgap is tuned by chlorine activation. The deposition of thin films and chlorine treatment were confirmed by elemental analysis. Surface topographical study reveals that the average roughness is increased with an annealing temperature up to 320 °C, while the I-V characteristics indicated ohmic nature of the contacts. The optimized results show that the NH4Cl-treated CdTe films annealed at 320 °C may be applicable as an absorber layer in solar cells.

Fabrication of Thin Film of Porous Silicon Using Electrodeposition Assisted Stripping (EAS) Process and Its Humidity Sensing Properties

Humidity is one of the most important factors in human life to live comfortably. Especially, detecting and measuring humidity has been attracted in various fields such as food science, meteorology, agriculture, and so on. At present, most of the humidity sensors, fabricated to detect humidity through variation of the electrical signals using metal oxide which was zinc oxide1, copper oxide2, titanium oxide3, conducting polymer4, and silicon based materials5-6. Especially, among the silicon based materials, porous silicon was currently one of the promising materials because of its easy fabrication process and low cost. Silicon is used as a key material for the electrical devices. The silicon occupies about 40 percent of the device production cost. Therefore, there were lots of study using spalling process for reducing the thickness of the silicon wafer. One of the most effective and inexpensive techniques is the Electrodeposition Assisted Stripping (EAS) process7. Electrodeposition assisted stripping (EAS) process was used to obtain a thin Si substrate by electroplating high tensile stress layer, which induced the lift-off behavior of thin Si layer. Ni buffer layer was deposited using electrodeposition process with the Watts bath. The buffer layer protects the Si substrate from the high stress layer which can cause damage to the substrate. Also, buffer layer thickness can control the spalled Si thickness. In this study, we fabricated thin porous Si using EAS process and thin porous Si was characterized as humidity sensor. The porous silicon was fabricated by dry etching process. Before the EAS process, titanium and nickel layer was deposited by E-beam evaporator. The thickness of titanium and nickel layer was 20 nm and 200 nm, respectively. The thickness of thin porous Si layer was controlled by controlling current density of Ni electrodeposition process. The current density was controlled 10 mA/cm2 to 50 mA/cm2. The thickness of spalled porous silicon layer was controlled 100 um to 60 um. Surface morphology, and thickness of porous Si layer were observed with a field emission scanning electron microscope (FE-SEM). Electrical characteristics of porous Si humidity sensor were measured by 2-point probe station. The humidity was controlled by changing the ratio of dry gas to wet gas. The resistance of humidity sensor was recorded using an electrical source meter. The sensitivity is represented by RDry/RRH, where RRH is the resistance with the varied humidity and RDry is the resistance with the lowest humidity. Moreover, response and the recovery time are defined as the time to reach 90% of the total variation. REFERENCES [1] Hsu, N.-F.; Chung, T.-K., “A rapid synthesis/growth process producing massive ZnO nanowires for humidity and gas sensing”. Applied Physics A 2014, 116 (3), 1261-1269. [2] Hsueh, H. T.; Hsueh, T. J.; Chang, S. J.; Hung, F. Y.; Tsai, T. Y.; Weng, W. Y.; Hsu, C. L.; Dai, B. T., “CuO nanowire-based humidity sensors prepared on glass substrate”. Sensors and Actuators B: Chemical 2011, 156 (2), 906-911. [3] Li, Z.; Zhang, H.; Zheng, W.; Wang, W.; Huang, H.; Wang, C.; MacDiarmid, A. G.; Wei, Y., “Highly Sensitive and Stable Humidity Nanosensors Based on LiCl Doped TiO2 Electrospun Nanofibers”. Journal of the American Chemical Society 2008, 130 (15), 5036-5037. [4] Hwang, L. S.; Ko, J. M.; Rhee, H. W.; Kim, C. Y., “A polymer humidity sensor”. Synthetic Metals 1993, 57 (1), 3671-3676. [5] P. Hurjes, A. Kovacs, Cs. Ducso, M. Adam, B. Muller, U. Mescheder, “Porous silicon-based humidity sensor with interdigital electrodes and internal heaters”, Sensors and Actuators B: Chemical 2003, 95, 140-144. [6] Z.M. Rittersma, A. Splinter, A. Bodecker, W. Benecke, “A novel surface-micromachined capacitive porous silicon humidity sensor” Sensors and Actuators B: Chemical 2000, 68, 210-217. [7] Youngim Kwno, Changwol Yang, Sang-Hwa Yoon, Han-Don Um, Jung-Ho Lee and Bongyoung Yoo, “Spalling of a Thin Si Layer by Electrodeposit-Assisted Stripping”, Applied Physics Express, 2013, 6 (11), 116502.

Ar+ Ion Implantation Induced Surface, Structural and Optical Modifications in Cadmium Selenide Thin Films

Among the groups II–VI semiconductors, cadmium selenide (CdSe) is a direct and wide band gap semiconductor. In comparison to Si films, CdSe semiconducting thin film have superior carrier mobility and, therefore, can be employed in solar cells as an absorber layer. In the present work, firstly thin films of CdSe were electrodeposited on the indium doped tin oxide (ITO) substrates. For the deposition, a bath containing cadmium sulfate and selenium dioxide solution was used. Prior to electrodeposition, ITO substrates were cleaned by an ultrasonicator using de-ionized water and acetone to remove impurities. After successful deposition of the film of thickness 120 nm, these were characterized by UV–Visible spectrophotometer, RF-530 Spectrofluorophotometer and four-probe setup with programmable current–voltage (I–V) source meter. The as-deposited CdSe thin films were implanted with 80 keV Ar+ ions at different fluencies i.e. 1 × 1015 ions/cm2, 5 × 1015 ions/cm2, 1 × 1016 ions/cm2 and 5 × 1016 ions/cm2. The effect of Ar+ ion implantation on the surface properties of CdSe thin films is studied with respect to lattice disorder. Defects created on implantation may give rise to new energy levels within the energy band gap that may serve as the trapping or recombination centers for the charge carriers depending upon the positions of the new energy levels. This alters the properties of the material and hence the characteristics of the device based upon the material.

Structural evolution, optoelectrical and corrosion properties of electrodeposited WO3 integration on Zn-TiO2 electrolyte for defence super application

Abstract Multifunctional nano composite coatings of Zn-TiO 2 -WO 3 were deposited electrolytically on mild steel (MS) from Zn bath, having Zn 2+ ions and uniform dispersion of TiO 2 and WO 3 nano particulates. The electrical, optical and corrosion resistance characteristics of the electrocodeposited coatings were assessed by Keithley 2400 Series Source meter with Multimeters, Newport Solar Simulator and a PGSTAT30 Autolab potentiostat respectively. The morphological characteristics of the composite coatings were characterized by scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS). The result revealed that the electrocodeposits showed good stability and Zn-TiO 2 -WO 3 nanocomposite deposits displayed enhanced microstructural qualities, good electrical conductivity and exhibited enriched corrosion resistance.

List of abstracts

. Results obtained in the analysis of single layer and multilayered carbon stacks produced by PLD at low temperature will be presented. The mechanical properties of carbon single layers deposited at various laser pulse fluences, like hardness and elasticity, were determined by means of nano indentation measurements. It will be shown that a wide variety of mechanical properties can easily be adjusted by adapting the process parameters.

Effect of SHI on properties of template synthesized Cu nanowires

Metallic as well as semiconducting nanostructures have generated wide interest and are achieving growing importance because of their potential applications in various devices, such as batteries, manufacturing of electrical contacts in microelectronics, MEMS, and solar cells. In the present work, template synthesis method coupled with electrodeposition has been used to synthesize copper nanowires of diameter 200 nm into the pores of a polycarbonate track-etched (PCTE) membrane. The synthesized Cu nanowires were irradiated with 150-MeV Ti9+ swift heavy ions at Inter University Accelerator Centre (IUAC), New Delhi, India. The pristine and irradiated nanowires were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), and Keithley 2400 series source meter to study their structural, morphological, elemental, and electrical properties, respectively. XRD analysis confirmed the face-centered cubic crystal system for pristine as well as irradiated samples. The lattice strain and crystallite size were evaluated using line broadening analysis methods following modified Scherrer method. Theoretical calculations have been done to obtain Young’s modulus of the nanowires and that has further been used to evaluate stress generated in the nanowires. Hall-Petch relation has been used to evaluate the change in strengthening coefficient in the nanowires due to irradiation. SEM analysis confirmed the cylindrical morphology of wires with a uniform diameter throughout the complete length of the wires. A change in electrical conductivity of the nanowires has been observed with increase in the fluence which is attributed to change in the orientation of grain boundaries and formation of defects.

Fabrication and Characterization of Organic Photovoltaic Cell using Keithley 2400 SMU for efficient solar cell

An organic solar cell device or organic photovoltaic cell (OPV) is a class of solar cell that uses conductive organic polymers or small organic molecules for light absorption and charge transport. In this study, we fabricate and characterize an organic photovoltaic cell device and estimated important parameters of the device such as Open Circuit Voltage Voc of 0.28V, Short-Circuit Current Isc of 4.0 × 10-5 A, Maximum Power Pmax of 2.4 × 10-6 W, Fill Factor of 0.214 and the energy conversion efficiency of η=0.00239% were tested using Keithley 2400,source meter under A.M 1.5 (1000/m2) illumination from a Newport Class A solar simulator. Also the I-V characteristics for OPV were drawn.

Environment approachable dye sensitized solar cell using abundant natural pigment based dyes with solid polymer electrolyte

In the present work dye sensitized solar cells were fabricated using natural pigment based dye extracted from different fruits as ‘sensitizer’. The photovoltaic properties of FTO coated thin film and extracted natural dyes were studied using UV–vis-NIR spectroscope. FTO coated subtract showed complete transmittance above 350 nm wavelength that is wide-ranging visible region and above wavelength, which is the desired property for solar cells. The extracted fruits and plants dye showed absorption up to 600 nm wavelength of incident light with wide range abssorption. The TiO2 thin films were prepared on FTO coated conducting substrate using doctor blade technique as photo anode while fruits and plants dye extracted in ethanol was used as sensitizes. The fabricated solar cells were characterized using Keithley source meter which shows that photovoltaic performance is relatively compared with popular expensive dyes i.e. N3, black and ruthenium.

CdS sensitized pristine and Cd doped ZnO solar cells: Effect of SILAR cycles on optical properties and efficiency

We report the CdS sensitized pristine and Cd doped ZnO using a successive ionic layer adsorption and reaction (SILAR) technique towards solar cell application. The effect of number of CdS SILAR cycles on the performance of pristine and Cd doped ZnO solar cells have been studied. A chemical synthesis technique at relatively low temperature (70 °C) was employed for the preparation of nanoparticulate powders of ZnO and Cd: ZnO. Doctor blade technique was used towards the preparation of film. The sensitization of CdS was done over ZnO and Cd: ZnO films with different SILAR cycles (4–16). The UV–Vis clearly shows the significant change in absorbance with the number of SILAR cycles for both the films. The results of J-V measurements with polysulfide as electrolyte and CuS as counter electrode were obtained by using 2420 Keithley source meter. The maximum power conversion efficiency of 0.279% and 0.604% was obtained for 12 cycles CdS sensitized ZnO and Cd: ZnO based solar cells, respectively.

Enhancement in microstructural and optoelectrical properties of thermally evaporated CdTe films for solar cells

The optimization of microstructural and optoelectrical properties of a thin layer is an important step prior device fabrication process, so an enhancement in these properties of thermally evaporated CdTe thin films is reported in this communication. The films having thickness 450 nm and 850 nm were deposited on thoroughly cleaned glass and indium tin oxide (ITO) substrates followed by annealing at 450 °C in air atmosphere. These films were characterized for microstructural and optoelectrical properties employing X-ray diffraction, scanning electron microscopy coupled with energy-dispersive spectroscopy, UV-Vis spectrophotometer and source meter. The films found to be have zinc-blende cubic structure with preferred reflection (111) while the crystallographic parameters and direct energy band gap are strongly influenced by the film thickness. The surface morphology studies show that the films are uniform, smooth, homogeneous and nearly dense-packed as well as free from voids and pitfalls as where elemental analysis revealed the presence of Cd and Te element in the deposited films. The electrical analysis showed linear behavior of current with voltage while conductivity is decreased for higher thickness. The results show that the microstructural and optoelectrical properties of CdTe thin layer could be enhanced by varying thickness and films having higher thickness might be processed as promising absorber thin layer to the CdTe-based solar cells.

Electrical switching behavior of bulk AgI-Ag2O-MoO3 glass with ON-state current and thickness

Bulk AgI-Ag2O-MoO3 (50:25:25) glasses have been prepared by melt quenching method (Microwave heating and quenched between two heavy steel plates). The electrical switching experiments have been carried out using a Keithley Source Meter (model 2410) controlled by Lab VIEW 6i, on samples of thicknesses 0.1, 0.2 and 0.3 mm at different ON state currents (3 mA, 2 mA, 1 mA, 0.6 mA, 0.4 mA and 0.25 mA). The samples are found to exhibit fast memory switching. The power dissipation increases with both thickness and ON state current. The threshold voltage, VTH increases with thickness; and for a given thickness, the VTH decreases with increasing ON state current. A sample of thickness 0.1 mm exhibits near ideal memory switching with the least power dissipation for an ON state current of 0.25 mA. The samples studied can be used for fast switching applications with minimum power dissipation.

Investigation on voltaic effect based on one-dimensional TiO2 nanotube array thin film

This work is to develop a high-reliability long-life high-conversion-efficiency radio-isotope microbattery in order to meet power requirements of micro-electromechanical systems, micro-sensors, micro-actuators, wireless sensing net, and other electron devices working in harsh circumstances, such as polar, desert, subsea, outer surface, etc. Compared with traditional dry batteries, chemical batteries, fuel cells and solar cells, the radioactive isotope batteries have long service life, higher energy density, strong adaptability to environment, good work stability, no maintenance, and miniaturized size, etc. These advantages make the voltaic battery an attractive alternative. In this paper we present a voltaic battery with enhanced voltaic effect by using a wide-bandgap semiconductor TiO2 nanotube array thin film. An electrochemical anodic oxidation method is used to prepare the vertically oriented and highly ordered TiO2 nanotube array film on Ti plate. Electrolyte solution consists of ammonium fluoride, ethylene glycol, and deionized water. The structure (TiO2 nanotube array with diameter about 80-100 nm, wall thickness about 15-25 nm, and length 9 m) is characterized by field emission scanning electron microscope. The microstructure of the TiO2 nanotube array is characterized using X-ray diffraction. The effects of annealing condition on optical and electrical properties are studied. The electrical property is characterized by Keithley model 2450 source meter semiconductor characterization system in dark at room temperature. The voltaic batteries are assembled as a sandwiched structure (63Ni/TiO2 nanotube arrays film/Ti) using a radioisotope 63Ni plate and TiO2 nanotube array films. The experimental results show that the black TiO2 nanotube array film annealed at 450 ℃ in argon atmosphere could creates high visible-ultraviolet absorption due to a great many of oxygen vacancy defects generated in TiO2 nanotube array film. The oxygen vacancy signals are found by electron spin resonance. Compared with the planar structure, the nano-porous array structure has strong absorption to particles:most of the particles enter into the pores and are reflected or absorbed by the surface of the tube walls. With a 10 mCi 63Ni radiation source, the voltaic battery using black TiO2 nanotube array film can generate an open-circuited voltage of 1.02 V, a short-circuited current of 75.52 nA, and a maximum effective conversion efficiency of 22.48%.

Polyaniline nanoparticles for the selective recognition of aldrin: Synthesis, characterization, and adsorption properties

We report the preparation, characterization, and property evaluation of molecularly imprinted polyaniline nanoparticles that can be used for the selective recognition of aldrin. The molecularly imprinted polyaniline nanoparticles were prepared by inverted emulsion polymerization using aldrin as a template and aniline as a functional monomer. The prepared nanoparticles were characterized using UV–vis spectroscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The spectral data confirmed that aldrin was successfully incorporated into the polymer matrix. Atomic force microscopy and scanning electron microscopy analyses revealed that the prepared nanoparticles were spherical in nature with sizes ranging from 60 to 100nm for nonimprinted particles and from 500 to 1500nm for imprinted particles. The surface morphology changed from smooth to rough upon the incorporation of aldrin molecules. The electrical properties were evaluated using a four-point probe coupled to a source meter. The nonimprinted nanoparticles showed an electrical conductivity of 4.149S/cm, which was reduced to 0.546S/cm in molecularly imprinted polyaniline. The equilibrium dissociation constant and free equilibrium concentration were found to be 0.6 and 0.799ng/μL, respectively. The adsorption characteristics of aldrin and dichlorodiphenyltrichloroethane (DDT) were investigated to determine the selectivity of the imprinted nanoparticles. The distribution coefficients for DDT and aldrin were 0.76ng/ng and 1.31μL/ng, respectively, indicating that the imprinted nanoparticles had a stronger affinity for aldrin than for DDT.