Equivalent series resistance

About: Equivalent series resistance is a research topic. Over the lifetime, 5335 publications have been published within this topic receiving 83362 citations. The topic is also known as: ESR.

Spatially resolved series resistance of silicon solar cells obtained from luminescence imaging

Abstract: The fast determination of the spatially resolved series resistance of silicon solar cells from luminescence images is demonstrated. Strong lateral variation of the series resistance determined from luminescence images taken on an industrial screen printed silicon solar cell is confirmed qualitatively by a Corescan measurement and quantitatively by comparison with the total series resistance obtained from the terminal characteristics of the cell. Compared to existing techniques that measure the spatially resolved series resistance, luminescence imaging has the advantage that it is nondestructive and orders of magnitude faster. © 2007 American Institute of Physics. DOI: 10.1063/1.2709630 The series resistance of silicon solar cells often exhibits strong lateral variations, particularly in industrial screen printed cells. Experimental techniques to quantify such variations include Corescan, 1 Cello, 2 and imaging techniques based on dark and illuminated infrared lock-in thermography LIT. 3,4 These techniques require data acquisition times between minutes and several hours per solar cell. Electroluminescence EL and photoluminescence PL imaging are very fast characterization tools for silicon solar cells and silicon wafers, with data acquisition times of a few seconds or less per sample. 5,6 Using EL images and PL images taken with external control of the voltage to measure lateral variations of the series resistance in silicon solar cells was proposed in Ref. 7. Some preliminary qualitative results were also reported. 7,8 Here, we demonstrate a quantitative determination of the series resistance and its lateral variation in a monocrystalline industrial screen printed silicon solar cell by luminescence imaging. Photoluminescence images are taken using an 815 nm/25 W laser that is expanded to illuminate the cell area of 12.512.5 cm 2 homogeneously with up to 0.67 Sun equivalent illumination intensity. A thermoelectrically cooled silicon charge coupled device camera is used to capture luminescence images. For the PL images with simultaneous current extraction, two arrays of ten spring loaded contact pins are used to contact the busbars of the cell homogeneously. A commercially available instrument is used for Corescan measurements; illuminated IV curves are measured with a calibrated industrial cell tester. In a simplified case, a solar cell is described as a twodimensional network of parallel nodes, with each node consisting of a series connection of a local resistor Rs,i and a diode. The value of R s,i is given as

Modeling the Electrical and Thermal Response of Superconducting Nanowire Single-Photon Detectors

Abstract: We modeled the response of superconducting nanowire single-photon detectors during a photodetection event, taking into consideration only the thermal and electrical properties of a superconducting NbN nanowire on a sapphire substrate. Our calculations suggest that heating which occurs after the formation of a photo-induced resistive barrier is responsible for the generation of a measurable voltage pulse. We compared this numerical result with experimental data of a voltage pulse from a slow device, i.e. large kinetic inductance, and obtained a good fit. Using this electro-thermal model, we estimated the temperature rise and the resistance buildup in the nanowire, and the return current at which the nanowire becomes superconducting again. We also show that the reset time of these photodetectors can be decreased by the addition of a series resistance and provide supporting experimental data. Finally we present preliminary results on a detector latching behavior that can also be explained using the electro-thermal model.

Gate-voltage-dependent effective channel length and series resistance of LDD MOSFET's

Abstract: A measurement algorithm to extract the effective channel length and source-drain series resistance of MOSFET's is presented. This extraction algorithm is applicable to both conventional and LDD MOSFET's. It is shown that the effective channel length and the source-drain series resistance of an LDD device are gate-voltage dependent. The effective channel length of an LDD device is not necessarily the metallurgical junction separation between the source and drain as it is commonly seen in a conventional device. A more generalized interpretation of effective channel length is introduced to understand the physical meaning of this gate-voltage dependence. The result also indicates that the effective channel length and source-drain resistance are two inseparable device parameters regardless of LDD or conventional FET's.

Improvement of the quality factor of RF integrated inductors by layout optimization

Abstract: A systematic method to improve the quality (Q) factor of RF integrated inductors is presented in this paper. The proposed method is based on the layout optimization to minimize the series resistance of the inductor coil, taking into account both ohmic losses, due to conduction currents, and magnetically induced losses, due to eddy currents. The technique is particularly useful when applied to inductors in which the fabrication process includes integration substrate removal. However, it is also applicable to inductors on low-loss substrates. The method optimizes the width of the metal strip for each turn of the inductor coil, leading to a variable strip-width layout. The optimization procedure has been successfully applied to the design of square spiral inductors in a silicon-based multichip-module technology, complemented with silicon micromachining postprocessing. The obtained experimental results corroborate the validity of the proposed method. A Q factor of about 17 have been obtained for a 35-nH inductor at 1.5 GHz, with Q values higher than 40 predicted for a 20-nH inductor working at 3.5 GHz. The latter is up to a 60% better than the best results for a single strip-width inductor working at the same frequency.