Automation Measurement System of Semiconductor Devices Parameters

Often, a depressed fill factor is observed in organic solar cells (OSCs), which is usually known as S-shaped current-voltage (J−V) characteristics. To investigate the origin of the depressed fill factor further, a poly[N-9-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)]:[6,6]-phenyl C71 butyric acid methyl ester based OSC has been characterized through impedance spectroscopy. In addition, the photocurrent vs the applied effective bias plot reveals that the S-shaped J−V characteristics primarily reduce the diffusion current of the device. The present study shows that the diffusion current dominated section of photocurrent reduces with a slope of 2 in the depressed fill factor section given that the slope may further increase as per the impact of the S-shape. The reduction in the diffusion constant (Dn) in the S-shaped region supports the decrease in the diffusion current, which is observed through the photocurrent analysis. It is observed that, in the S-shaped section of the current-voltage characteristics, the transport time for free carriers increases up to 443 μs. The larger Urbach energy for the active layer of an S-shaped device demonstrates higher subbandgap disorder. Therefore, it is concluded that the accumulation of the charge carriers within the device and disorder in the active layer leads to the S-shaped current–voltage characteristics as well as poor carrier extraction.

We have investigated the effect of the light‐induced deep‐level recombination centre specific to boron‐doped, oxygen‐contaminated Czochralski (Cz) silicon on the current–voltage characteristic of Cz silicon solar cells by means of numerical simulation and experiment. The device simulation predicts the occurrence of a shoulder in the current–voltage curve after activating the characteristic recombination centre. The physical reason for the non‐ideal diode behaviour, characterised by a local ideality factor greater unity, is the strongly injection‐level‐dependent bulk lifetime produced by the deep‐level centre. The increased ideality factor causes a degradation in fill factor with the magnitude of degradation depending on the doping concentration of the Cz silicon base. In order to verify the theoretical predictions experimentally, we have performed measurements on high‐efficiency Cz silicon solar cells. Current–voltage curves recorded before and after light degradation clearly show the theoretically predicted change in shape and the reduction in fill factor. An excellent quantitative agreement between calculation and experiment is obtained for the subtracted current–voltage curves measured after and before illumination. Copyright © 2001 John Wiley & Sons, Ltd.

The current–voltage characteristic of magnetospheric magnetic flux tubes is studied under rather general conditions, assuming the current to be carried by collision‐free particles experiencing inertia, electric forces, and magnetic mirror forces. The approach is that of the powerful kinetic “orbital motion” theory of current collectors in plasma as developed by H. M. Mott‐Smith and I. Langmuir in 1926. When C. Davisson's 1925 condition on particle access is fulfilled, the total voltage drop is uniquely determined from the current by kinetic/geometric considerations only, without considerations of the actual space charge and electrostatic potential distribution. For any velocity distribution that is isotropic within the source cone, the current–voltage characteristic is linear for sufficiently small currents. The nature of the corresponding global flux tube electric resistance is discussed. The current–voltage characteristic is given for a variety of distribution functions (where the Maxwellian case corresponds to that studied by S. Knight in 1973) including distributions with a reduced (nonisotropic) flux in the source cone. The current–voltage characteristic is also discussed for cases where the Davisson condition is not fulfilled, when the solution method provides a lower bound on the voltage for a given current. Making assumptions on the altitude extent of the voltage drop, we can also define an upper bound on the voltage for a particular current. The magnetospheric source of particles should be taken to be located at the top of the acceleration region in order to fulfill the Davisson condition. This may limit the effective magnetic mirror ratio, such that the applicability of the linear approximation to the current–voltage characteristic is more restricted, and the saturation current is moderately small, which may lead to overvoltages, a redistribution of the current, or an increased extent of the acceleration region. Joining solutions that piecewise fulfill the Davisson condition, we can derive the current flow for a rather wide range of prescribed potential distributions. Earlier works on the Knight mechanism and related theories for determining the voltage drop along a flux tube are discussed. Determination of the electrostatic potential distribution, and verification of the Davisson condition, requires considerations of the space charge (Poisson equation), to be discussed in a second paper.

Analytical solutions using special trans functions theory for current–voltage expressions of perovskite solar cells and their approximate equivalent circuits

Vision measuring, involving the measurement of the three-dimensional shape and color of large objects using stereo vision-based methods, is a challenging task. In this study, a freely adjustable vision measurement system for large objects is developed by connecting a camera to a total station telescope via a fixed mount. In this system, a camera is focused on the target object to be measured in far-range scenarios. A high-precision calibration method is proposed based on non-parametric camera models. In addition, a point cloud-based three-dimensional reconstruction method is developed by integrating with the non-parametric camera models. The experimental results showed that the proposed system has high precision and robustness. When measuring objects from a distance of 8m in an indoor scenario, the error in the maximum spatial distance measurement between two corner points on the calibration board is less than 0.24mm. The maximum relative measurement error is less than 0.09%. When measuring an object 20m away in an outdoor scenario, the average error in the spatial distance measurement between two arbitrary points in an 11 m×4 m testing region is 5.6mm. The average relative error in the distance measurement is 0.12%.

The authors report an enhanced infrared spectral response of GaAs-based solar cells that incorporate type II GaSb quantum dots (QDs) formed using interfacial misfit array growth mode. The material and devices, grown by molecular beam epitaxy, are characterized by current-voltage and spectral response characteristics. From 0.9to1.36μm, these solar cells show significantly more infrared response compared to reference GaAs cells and previously reported InAs QD solar cells. The short circuit current density and open circuit voltages of solar cells with and without dots measured under identical conditions are 1.29mA∕cm2, 0.37V and 1.17mA∕cm2, 0.6V, respectively.

Deposition of earth-abundant p-type CuBr films with high hole conductivity and realization of p-CuBr/n-Si heterojunction solar cell

The aim of this paper deal with the mathematical modelling approach and behaviour of thin-film a-Si: H solar cells. The current-voltage (I-V) curve presents double linearities on the cell parameters and the exponential. So, thin-film P-I-N solar cell (a-Si-H) based on the classic combination of diode with an exponential I-V characteristics and adding a new current named recombination loss. The fundamental understanding of parasitic parameters will be discussed, and an equivalent circuit used in the research to study thin-film P-I-N structures is described. This work will show the mathematical modelling and prediction of dynamic resistance and short circuit current and open-circuit voltage resistance. The impact of parameters on the performance of an a-Si: H solar cell in different solar irradiations is more difficult to comprehend than that of crystalline silicon. As a result, adding an additional diode to the model can help for a more thorough investigation of the degradation process, particularly the Staebler-Worski effect. The parasitic resistance and dynamic resistance are determining in open-circuit voltage and short circuit current. Finally, the experimental I-V and P-V curves are displayed to investigate the various irradiation intensities.

Analysis of temperature dependent electrical properties of Au/perylene-diimide/n-Si Schottky diodes

A physical-chemistry study of a Nafion 117 membrane is undertaken and a correlation between the transport number and current–voltage data of this cation exchange membrane is established. The current–voltage characteristics of the membrane are obtained with the voltamperometric technique, by means of two feed platinised titanium electrodes and two measuring silver–silver chloride electrodes. Previous measurements show that the membrane presents low electrical resistance and weak permselectivity towards the proton in the presence of other metallic cations. However, its chemical modification with the conducting polymer highly improves the proton conduction and gives better selectivity towards the monovalent cation (Na+) against the divalent cation (Zn2+). The effects of the co-ion (anion), charge, solvent and chemical modification are made in evidence by the current–voltage curves. As a result of its pre-concentration near the anionic layer, the divalent cation increases the value of the limiting current density. Besides, the presence of an organic solvent inside the polymeric matrix of the membrane decreases the limiting current density. Different graphical methods are applied to deduce the limiting current density and the derivative method is found to be more reliable.

Effect of anionic and cationic exchange polymeric layers on current–voltage curves and chronopotentiometry of a charged composite membrane

Real-time crop harvest data acquisition from harvesters during harvesting operations is an important way to understand the distribution of crop harvest in the field. Most real-time monitoring systems for grain yield using sensors are vulnerable to factors such as low accuracy and low real-time performance. To address this phenomenon, a real-time grain yield monitoring system was designed in this study. The real-time monitoring of yield was accomplished by adding three pairs of photoelectric sensors to the elevator of the corn kernel harvester. The system mainly consists of a signal acquisition and processing module, a positioning module and a visualization terminal; the signal acquisition frequency was set to 1 kHz and the response time was 2 ms. When the system operated, the signal acquisition and processing module detected the sensor signal duration of grain blocking the scrapers of the grain elevator in real-time and used the low-potential signal-based corn grain yield calculation model constructed in this study to complete the real-time yield measurement. The results of the bench tests, conducted under several different operating conditions with the simulated elevator test bench built, showed that the error of the system measurement was less than 5%. Field tests were conducted on a Zoomlion 4YZL-5BZH combined corn kernel harvester and the results showed that the average error of measured yield was 3.72%. Compared to the yield measurement method using the weighing method, the average error of the bench test yield measurement was 7.6% and the average error of yield measurement in field trials with a mass flow sensor yield measurement system was 16.38%. It was verified that the system designed in this study has high yield measurement accuracy and real-time yield measurement, and can provide reference for precision agriculture and high yield management.

Because of their state of art technology, GaAs solar cells are generally preferred for spatial applications. Exposure to proton and electron irradiations, solar cells suffer significant degradation in their performance such as short circuit current and open circuit voltage. Adding a window layer helps in effectively reducing the surface recombination at the emitter surface of the solar cell without absorbing the useful light required for the device. It remains to study the physics of the window-emitter hetero-interface in order to understand how the window layer presence increases the minority carrier lifetime of the solar cell exposed to particles irradiation. In this work Numerical simulation has been used to study the AlxGa1- xAs window composition effect on the current-voltage characteristics of a GaAs solar cell under AM0 illumination and exposed to 1 MeV electron irradiation. To predict the effect of window layers on solar cells degradation, the current voltage characteristic are evaluated for different electron irradiation fluences. The findings are supported by experimental data. They lead us to get to know how the window layer improves resistance to electron irradiation through its own parameters.

Current–voltage and capacitance–voltage characteristics of Al/p-type silicon/organic semiconductor based on phthalocyanine rectifier contact

The current voltage characteristic of the Na, K pump is described on the basis of a modified Post-Albers cycle. The voltage dependence of the rate constants is derived from the elementary chargetranslocations associated with the single reaction steps. Charge displacements result from movements of the sodium- or potassium-loaded binding sites, as well as from motions of polar groups in the pump molecule. If part of the transmembrane voltage drops between the alkali-ion binding sites and the aqueous solution, the binding constants become voltage-dependent. Depending on the values of the microscopic parameters, the current-voltage characteristic may assume a variety of different shapes. Saturating behaviour results when one or more voltage-independent reaction steps become rate limiting. Non-monotonic current-voltage curves exhibiting regions of negative pump conductance are predicted when, at least in one of the transitions, charge is moved against the direction of overall charge-translocation. The theoretical predictions are compared with recent experimental studies of voltage-dependent pump currents.