Papers by Keyword: Current-Voltage

Abstract: A new set of nanocrystals of carbon nanospheres (5%, 10%, and 15% by weight) were synthesized and were anchored to cobalt based metal-organic frameworks (Co-MOFs). They were synthesized using the organic linker, 4-{[(1E)-1-hydroxy-3-oxoprop-1-en-2-yl]sulfanyl}benzoic acid (4-HSPBA) via solvothermal synthesis. The synthesized materials were characterized for structural and morphological properties by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) surface area analysis. The electrochemical characteristics of the obtained Co-MOFs and carbon nanosphere-contained Co-MOF nanocomposites were investigated comprehensively by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The EIS tests revealed the characteristic current-voltage properties of pristine Co-MOFs and carbon nanosphere-doped Co-MOFs. While the undoped Co-MOF exhibited nearly linear current-voltage behavior, introduction of carbon nanospheres at increasing concentrations (5 wt.%, 10 wt.%, and 15 wt.%) resulted in very high non-linearity in the current-voltage response. The reason for non-linearity is a synergistic effect between carbon nanospheres and the Co-MOF matrix, which greatly influences the transport pathways for charges and enhances electrical conductivity. Further, morphological analysis confirmed the formation of heterostructured architectures with spherical shapes of uniform nature irrespective of doping level. The findings reveal the carbon nanosphere-modified Co-MOFs as promising electrode materials for supercapacitors with improved electrochemical attributes. Besides energy storage applications, the nanostructured materials are poised to revolutionize photonics, optoelectronics, and other emerging next-generation energy-related technologies.

Abstract: Present work illustrates synthesis of Cr doped WO₃ nanostructures (NS) (2 wt. %, 4 wt. % and 6 wt. %) by co precipitation method using surfactants and reported enhanced impedance, capacitance-voltage and current-voltage (I-V) characteristics. NS were characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Visible (UV-Vis) spectroscopy, pelletized samples performed I-V, C-V and impedance measurements. Impedance results reveal that the pelletized samples of highest doped Cr showed remarkable increase in admittance with respect to the biased voltage. I-V characteristics of highest doped Cr exhibited enhanced surface conductivity as compared with applied current. The output power considerably increases for the 6 wt. % of Cr doped WO₃ and doping percentage of Cr increases surface conductivity, power output, admittance considerably enhances in the material matrix. This work demonstrated that Cr doped WO₃ has more sensitivity towards I-V, C-V and impedance value considerably varies with the applied bias voltage. The limitation is not certain in case of doped nanomaterials of Cr-WO₃, since these materials possesses nonlinear properties and can find applications in the diversified filed of nano electronics. The authors reported work can be a key guide for the upcoming researchers in the area of biomedical devices, nanoelectronics, sensors, wherein Cr-WO₃ NS finds applications because of its enhanced I-V, C-V, Impedance characteristics. The work has been carried out to understand the electrical and electronic properties of doped nanomaterials in the original work place and analysis has been carried out at various institutions where the provisions for the experimentation is being made.

Abstract: In this paper, the detail study of electrical conductivity of single layer graphene (SLG) on silicon dioxide (SiO₂)/Silicon substrate irradiated by high energy (MeV) electron is presented. The SLG samples prepared by Chemical Vapor Deposition (CVD) were irradiated by 50 kGy, 100 kGy and 200 kGy doses of electron radiation at energy voltage of 3 MeV. Current-Voltage (I-V) characteristics and conductivity of the pristine and irradiated graphene samples were measured and analysed using I-V measurement at room temperature. The non-linear I-V curves were clearly observed as the voltage reach to 2.0 V for non-irradiated and irradiated samples. This may be attributed to the non-uniform charges by high energy electron irradiation and poor metal contact of the sample. Hysteresis loop form at 2.0 V probably due to the to the charge trapping occurs at the interface of the graphene and SiO_2. The reaction of high energy particles lead to creation of more carrier charges that contribute to the increment of conductivity compare to the small number of atom displacement of knock-on collisions with the nuclei of carbon atoms at higher dose. This study provides significant findings on the graphene electrical characteristics when irradiated with high energy (MeV) electron.

Abstract: The major differences between dye sensitized solar cell (DSSC) and p-n junction solar cells are spectrum absorption range, photoelectric conversion response time and standard test condition (STC). The operation principle of DSSC is using layers of organic molecules subject to lighting after excitation electronic then pass to the inorganic/organic layer of the wide energy gap nanolayer and voltage. Therefore, characterizations of DSSC are important in order to clarify how to determine its performance accurately. Such measurement requires considering the different level lighting on each very slow temporal response (hysteresis and transient) in its current-voltage (I-V) curves, which are dependent on the voltage sweep direction, even when the sweep time is the order of seconds. This paper presents a new test method for determining I-V performance of DSSC, which differs with IEC 60904-1 addressed on single and multi-junction samples. Results were applied to SEMI Doc. 5597 and released as SEMI PV57 by voting in 2014. Consequently, emerging photovoltaic device makers and buyers, or any other party interested, can thus have a common testing standard to refer to when desired.

Abstract: With increasing applications in consumer electronics such as smart phones, laptops and tablet PCs, the need for pervasive computing with a requirement of lower power consumption is increasing every day. This opens the door for energy harvesting that could charge the batteries in these devices to keep them continually functioning in some useful state. There has been a lot of attention on flexible thin film solar cells, such as dye sensitized (DSC), organic and inorganic, given their low-cost and improving efficiency. Performance characterization DSC has been investigated, in order to clarify how to determine their performance accurately. Accurate characterization of DSC requires level lighting consideration on each very slow temporal response in the I-V curves of the DSC are clearly dependent on the voltage sweep direction, even when the sweep time is the order of seconds. Furthermore, the temporal response is dependent on different level lighting consideration. This analysis showed to improve accuracy, measurement should be real time removing capacitance effect with a Real-Time One-Sweep Method (RTOSM). Additionally, RTOSM will be useful to measuring cell performance more accurately and rapidly when evaluating solar cell performance.

Abstract: Electrical properties of Schottky contacts of high work-function metals (Pd, Au, and Ni) on (010) and (201) oriented β-Ga₂O₃ were investigated. Current-voltage characteristics reveal that all the contacts exhibit high rectifying behavior with ideality factors as low as 1.04. However, the reverse leakage currents were lower in the (010) samples compared to the (201) ones. Thermal admittance spectroscopy confirms a main charge carrier level to be at ~0.15 eV below the conduction band edge (E_c). Secondary ion mass spectrometry indicates that Si may be responsible for this donor level. Deep level transient spectroscopy reveals four levels (E1-E4) in the upper part of the band gap, with the corresponding energy level positions at 0.56, 0.76, 1.01, and 1.48 eV below E_c.

Abstract: The purpose of the paper is present the new result of electrical properties of Pt-doped silicon Schottky diodes that are fabricated by using CMOS technology. The results show the comparison of electrical properties namely current-voltage and capacitance characteristics between undoped and Pt-doped Schottky diode. The current characteristics of Pt-doped diode are decreased about 2 to 3 orders in term of reverse bias. As well as in case of forward bias, the current is slightly decreased. Schottky barrier height after Pt doping was increased from 0.84 eV to 0.86 eV. The built-in voltage of Pt-doped diodes was increased from 0.38 V to 0.42 V. The C-V characteristics after Pt doping is decreased about 5 pF. The change of electrical properties are caused by Pt because Pt atoms in silicon can occupy interstitial sites and change the trapping center. This paper will study and analyze the effect of Pt atom in silicon bulk of Schottky diode.

Abstract: An effect induced by x-ray irradiation on Boron-doped crystalline Si at room temperature was closely investigated in this paper. Irradiation of X-ray energy of 40, 55 and 70keV has been performed on P-N junction diodes fabricated at Thai Microelectronics Center. Minority carrier life time of the device has been calculated before and after irradiation for comparison. The results show no significant change on the value between exposed and unexposed device. Therefore, any permanent lattice modified or any defects caused by X-ray in the device bulk seem to be unconfirmed in this range of energy. However, from this study, X-ray irradiation still effects on electrical characteristics of the diodes. Current-voltage (I-V) measurement has been carried out to study characteristic variation of the device. Biasing of the device was performed from -10 to 1 V and, after the exposure, the leakage current was obviously decreased by 25% and forward current was dramatically increased by 3 order of magnitude related to increment of X-ray energy.

Abstract: Chemical composition and uniaxial compressive stress are varied to observe their effect on the current-voltage behaviors of ZnO based ceramics. Chemical composition variation produces two kinds of ceramics showing ohmic and nonohmic current-voltage behaviors. The current at a fixed voltage is increased with the increase of the compressive stress for both ceramics. Ceramics with nonohmic behavior shows better reversible return of current-voltage curve when the applied compressive stress is removed from the ceramic than those with ohmic behavior do. We found out an appropriate chemical composition showing linear relation between current and stress at a fixed voltage as a potential application of the ceramic material to pressure sensor.