Study of a-Si:H / c-Si Heterojunctions for PV Applications

1996 ◽  
Vol 420 ◽  
Author(s):  
F. Zignani ◽  
R. Galloni ◽  
R. Rizzoli ◽  
M. Ruth ◽  
C. Summonte ◽  
...  
Keyword(s):  
Gas Phase ◽  
Open Circuit Voltage ◽  
Accurate Determination ◽  
Electrical Characterization ◽  
Silicon Layer ◽  
Open Circuit ◽  
Hydrogen Dilution ◽  
Intrinsic Efficiency

Abstracta-Si:H / c-Si heterojunction diodes were produced by PECVD with varying amorphous silicon layer thickness and hydrogen dilution of the gas phase. An accurate determination of the growth rate also in the initial stages of the deposition was made possible by an original chemical method based on the dissolution of the films followed by spectroscopical analysis of the obtained solution.The electrical characterization of the diodes confirms the generation - recombination - multitunneling nature of the transport. Although H2 dilution is important, however, beyond a certain level it is detrimental for the junction quality, probably due to the transition to a microcrystalline phase deposition. Solar cells were also produced, the best results being an open circuit voltage of 610 mV and an intrinsic efficiency of 14.2%.

Overcoming the Challenges of Parallel, SRAM Shorts Test Structures with EBIRCH

2018 ◽  
Author(s):  
Noor Jehan Saujauddin ◽  
Lloyd Smith ◽  
Randy Newkirk ◽  
Kevin Davidson ◽  
Gregory M. Johnson ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Electrical Characterization ◽  
Advanced Technology ◽  
Massively Parallel ◽  
Resistance Change ◽  
Design Elements ◽  
Time Required ◽  
Technology Nodes

Abstract Massively parallel test structures, based on looking for shorts between certain design elements in the SRAM cells, are becoming increasingly relied upon in yield characterization. The localization of electrical shorts in these structures has posed significant challenges in advanced technology nodes, due to the size, and design complexity. Several of the traditional methods (nanoprobing, OBIRCH, etc.) are shown to be inadequate to find defects in SRAM cells, either due to resolution, or time required. In recent years, the Electron Beam Induced Resistance Change (EBIRCH) technique has increasingly been utilized for failure analysis. Combining EBIRCH with other techniques, such as SEM based nanoprobing system and PVC, allows not only direct electrical characterization of suspicious bridging sites but also allows engineers to pinpoint the exact location of defects with SEM resolution. This paper will demonstrate the several cases where SRAM-like test structures provided extreme challenges, and EBIRCH was the key technique towards finding the fail. A node to node, node to wordline, and ground-ground contact fails are presented. A combination of EBIRCH with the more traditional techniques in advanced technology node is key to timely and accurate determination of shorting mechanisms in our test structures.

scholarly journals Comparison of Elemental Analysis Techniques for the Characterization of Commercial Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 736
Author(s):  
Peter Seidel ◽  
Doreen Ebert ◽  
Robert Schinke ◽  
Robert Möckel ◽  
Simone Raatz ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Analytical Techniques ◽  
Optical Emission ◽  
Breakdown Spectroscopy ◽  
General Evaluation ◽  
Sample Composition ◽  
Laser Induced Breakdown ◽  
Copper Aluminum

Better quality control for alloy manufacturing and sorting of post-consumer scraps relies heavily on the accurate determination of their chemical composition. In recent decades, analytical techniques, such as X-ray fluorescence spectroscopy (XRF), laser-induced breakdown spectroscopy (LIBS), and spark optical emission spectroscopy (spark-OES), found widespread use in the metal industry, though only a few studies were published about the comparison of these techniques for commercially available alloys. Hence, we conducted a study on the evaluation of four analytical techniques (energy-dispersive XRF, wavelength-dispersive XRF, LIBS, and spark-OES) for the determination of metal sample composition. It focuses on the quantitative analysis of nine commercial alloys, representing the three most important alloy classes: copper, aluminum, and steel. First, spark-OES is proven to serve as a validation technique in the use of certified alloy reference samples. Following an examination of the lateral homogeneity by XRF, the results of the techniques are compared, and reasons for deviations are discussed. Finally, a more general evaluation of each technique with its capabilities and limitations is given, taking operation-relevant parameters, such as measurement speed and calibration effort, into account. This study shall serve as a guide for the routine use of these methods in metal producing and recycling industries.

Development and Characterization of a Multimycotoxin Reference Material

2019 ◽  
Vol 102 (6) ◽  
pp. 1642-1650 ◽  
Author(s):  
Melissa M. Phillips ◽  
Tomás M. López Seal ◽  
Jennifer M. Ness ◽  
Kai Zhang
Keyword(s):  
Interlaboratory Comparison ◽  
Accurate Determination ◽  
Data Sets ◽  
Mass Fractions ◽  
Adequate Quality ◽  
Multiple Sample ◽  
Lc Tandem Ms ◽  
The U.S

Background: Matrix-matched reference materials (RMs) are critical for adequate quality assurance of extraction, digestion, separation, and/or detection processes for analytes of interest in foods and dietary supplements. The accurate determination of mycotoxins in foods is an international concern. While RMs for mycotoxins are available from a variety of RM producers, these mainly address a single mycotoxin or group of mycotoxins and therefore require the use of multiple RMs for multitarget methods. Objective: To address the increasing needs of laboratories moving toward LC-MS-based multimycotoxin analysis, the U.S. National Institute of Standards and Technology (NIST) collaborated with the U.S. Food and Drug Administration (FDA) to produce a naturally incurred RM for multiple mycotoxins in corn. Methods: Homogeneity of the RM has been assessed using a stratified random sampling of the final product based on mycotoxin mass fractions measured by the FDA and NIST. Multiple sample sizes were evaluated to maximize homogeneity in the obtained results. The mycotoxin levels in the final materials have been evaluated via interlaboratory comparison and isotope dilution LC–tandem MS measurements made at the FDA and NIST. The final value assignment combined results from these data sets. Conclusions: The study successfully developed a certified RM, SRM 1565 Mycotoxins in Corn, and a workflow for the future development of multimycotoxin RMs in different matrices.

scholarly journals Softening of Shear Elastic Coefficients in Shape Memory Alloys Near the Martensitic Transition: A Study by Laser-Based Resonant Ultrasound Spectroscopy

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1383
Author(s):  
Petr Sedlák ◽  
Michaela Janovská ◽  
Lucie Bodnárová ◽  
Oleg Heczko ◽  
Hanuš Seiner
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Single Crystals ◽  
Accurate Determination ◽  
Martensitic Transition ◽  
Elastic Coefficient ◽  
Resonant Ultrasound Spectroscopy ◽  
Resonant Ultrasound

We discuss the suitability of laser-based resonant ultrasound spectroscopy (RUS) for the characterization of soft shearing modes in single crystals of shape memory alloys that are close to the transition temperatures. We show, using a numerical simulation, that the RUS method enables the accurate determination of the c′ shear elastic coefficient, even for very strong anisotropy, and without being sensitive to misorientations of the used single crystal. Subsequently, we apply the RUS method to single crystals of three typical examples of shape memory alloys (Cu-Al-Ni, Ni-Mn-Ga, and NiTi), and discuss the advantages of using the laser-based contactless RUS arrangement for temperature-resolved measurements of elastic constants.

Local bond order parameters for accurate determination of crystal structures in two and three dimensions

2018 ◽  
Vol 20 (42) ◽  
pp. 27059-27068 ◽  
Author(s):  
Hossein Eslami ◽  
Parvin Sedaghat ◽  
Florian Müller-Plathe
Keyword(s):  
Crystal Structures ◽  
Bond Order ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Order Parameters ◽  
Three Dimensions ◽  
Local Order ◽  
Crystalline Structures

Local order parameters for the characterization of liquid and different two- and three-dimensional crystalline structures are presented.

Characterization of Matrix-Assisted Laser Desorption Based on Absorption and Acoustic Monitoring

1995 ◽  
Vol 49 (12) ◽  
pp. 1826-1833 ◽  
Author(s):  
Jan Preisler ◽  
Edward S. Yeung
Keyword(s):  
Atmospheric Pressure ◽  
Accurate Determination ◽  
Optimal Conditions ◽  
Plume Velocity ◽  
Ion Laser ◽  
Optical Probing ◽  
Argon Ion ◽  
Reduced Pressures

Conventional methods for studying matrix-assisted desorption-ionization rely on mass spectroscopy. In this study, a 488-nm argon-ion laser beam is deflected by two acoustooptic deflectors to image plumes desorbed at atmospheric pressure via absorption. All species, including neutral molecules, are monitored. Interesting features, e.g., differences between the initial plume and subsequent plumes desorbed from the same spot, or the formation of two plumes from one laser shot, are observed. Total plume absorbance can be correlated with the acoustic signal generated by the desorption event. A model equation for the plume velocity as a function of time is proposed. Optical probing also enables accurate determination of plume velocities at reduced pressures. These results define the optimal conditions for desorbing analytes from matrices, as opposed to achieving a compromise between efficient desorption and efficient ionization as is practiced in mass spectrometry.

scholarly journals Characterization of Self-Heating Process in GaN-Based HEMTs

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1305 ◽  
Author(s):  
Daniel Gryglewski ◽  
Wojciech Wojtasiak ◽  
Eliana Kamińska ◽  
Anna Piotrowska
Keyword(s):  
Communication Systems ◽  
Accurate Determination ◽  
Heating Process ◽  
Equivalent Circuits ◽  
High Electron ◽  
Thermal Impedance ◽  
Self Heating ◽  
Gan Hemt

Thermal characterization of modern microwave power transistors such as high electron-mobility transistors based on gallium nitride (GaN-based HEMTs) is a critical challenge for the development of high-performance new generation wireless communication systems (LTE-A, 5G) and advanced radars (active electronically scanned array (AESA)). This is especially true for systems operating with variable-envelope signals where accurate determination of self-heating effects resulting from strong- and fast-changing power dissipated inside transistor is crucial. In this work, we have developed an advanced measurement system based on DeltaVGS method with implemented software enabling accurate determination of device channel temperature and thermal resistance. The methodology accounts for MIL-STD-750-3 standard but takes into account appropriate specific bias and timing conditions. Three types of GaN-based HEMTs were taken into consideration, namely commercially available GaN-on-SiC (CGH27015F and TGF2023-2-01) and GaN-on-Si (NPT2022) devices, as well as model GaN-on-GaN HEMT (T8). Their characteristics of thermal impedance, thermal time constants and thermal equivalent circuits were presented. Knowledge of thermal equivalent circuits and electro–thermal models can lead to improved design of GaN HEMT high-power amplifiers with account of instantaneous temperature variations for systems using variable-envelope signals. It can also expand their range of application.

scholarly journals Impedance Spectroscopic Investigation of the Degraded Dye-Sensitized Solar Cell due to Ageing

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Parth Bhatt ◽  
Kavita Pandey ◽  
Pankaj Yadav ◽  
Brijesh Tripathi ◽  
Manoj Kumar
Keyword(s):  
Current Density ◽  
Open Circuit Voltage ◽  
Electrochemical Impedance ◽  
Short Circuit ◽  
Dye Sensitized Solar Cells ◽  
Electrical Characterization ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Conduction Band Edge ◽  
Dye Sensitized

This paper investigates the effect of ageing on the performance of dye-sensitized solar cells (DSCs). The electrical characterization of fresh and degraded DSCs is done under AM1.5G spectrum and the current density-voltage (J-V) characteristics are analyzed. Short circuit current density (JSC) decreases significantly whereas a noticeable increase in open circuit voltage is observed. These results have been further investigated electroanalytically using electrochemical impedance spectroscopy (EIS). An increase in net resistance results in a lower JSC for the degraded DSC. This decrease in current is mainly due to degradation of TiO2-dye interface, which is observed from light and dark J-V characteristics and is further confirmed by EIS measurements. A reduction in the chemical capacitance of the degraded DSC is observed, which is responsible for the shifting of Fermi level with respect to conduction band edge that further results in an increase of open circuit voltage for the degraded DSC. It is also confirmed from EIS that the degradation leads to a better contact formation between the electrolyte and Pt electrode, which improves the fill factor of the DSC. But the recombination throughout the DSC is found to increase along with degradation. This study suggests that the DSC should be used under low illumination conditions and around room temperature for a longer life.

Sign in / Sign up

Export Citation Format

Share Document