Technical Abstracts
In Case You Missed It
Additive Manufacturing
“Charge Transport Mechanisms in Inkjet-Printed Thin-Film Transistors Based on Two-Dimensional Materials”

Authors: Erik Piatti, et al.

Abstract: Printed electronics using inks based on graphene and other 2-D materials can be used to create large-scale, flexible, wearable devices. However, the complexity of ink formulations and the polycrystalline nature of the resulting thin films have made it difficult to examine charge transport in such devices. Here the authors report the charge transport mechanisms of surfactant- and solvent-free inkjet-printed thin-film devices based on few-layer graphene (semimetal), molybdenum disulfide (MoS2, semiconductor) and titanium carbide MXene (Ti3C2, metal) by investigating the temperature, gate and magnetic-field dependencies of their electrical conductivity. (Nature Electronics, December 2021, https://www.nature.com/articles/s41928-021-00684-9)

Conformal Coatings
“Prediction of Solder Joint Reliability with Applied Acrylic Conformal Coating”

Authors: Duarte Nuno Vieira, et al.

Abstract: The exposure of miniaturized components to the environment leads to new failure analysis as a result of environmental conditions and constant innovation of the component materials and dimensions. Generally, these failures occur on the solder joints. Conformal coating encapsulates the components and their solder joints to protect against harsh environments. However, this application is not recommended in some component packages such as BGAs and QFNs, since it can reduce the reliability of the solder joints when exposed to temperature fluctuations. Therefore, by using a finite element analysis, a thermal cycle test was simulated with and without conformal coating. The simulation output was extrapolated to lifetime theoretical methods with the aim of predicting the number of cycles until the failure of the solder joints. This study demonstrates, for both components without conformal coating, solder joint lifetime was a precise approximation. Coated solder joints reveal a drastic reduction in reliability due to the influence of the conformal coating behavior and its thermomechanical properties. (Journal of Electronic Materials, January 2022, https://link.springer.com/article/10.1007/s11664-021-09232-9)

Flexible Electronics
“Stencil Printing of Liquid Metal upon Electrospun Nanofibers Enables High-Performance Flexible Electronics”

Authors: Dr. Zhao Gang, et al.

Abstract: Materials and fabrication technologies are key factors restricting the development and commercialization of flexible electronics. The authors report on a simple, fast, and green flexible electronics preparation technology. The stencil printing method is adopted to pattern liquid metal on the thermoplastic polyurethane membrane prepared by electrospinning. Besides, with layer-by-layer assembly, flexible circuits, resistors, capacitors, inductors, and their composite devices can be prepared parametrically. Furthermore, these devices have good stretchability, air permeability and stability, while they are multilayered and reconfigurable. This strategy is used to fabricate flexible displays, flexible sensors and flexible filters. Finally, flexible electronic devices are also recycled and reconfigured. (ACS Nano, November 2021, https://pubs.acs.org/doi/10.1021/acsnano.1c05762)

Optical Computing
“All-Optical Computing Based on Convolutional Neural Networks”

Authors: Dr. Xiaoyong Hu and Dr. Qihuang Gong

Abstract: The scaling of computing speed is limited not only by data transfer between memory and processing units, but also by RC delay associated with ICs. Moreover, excessive heating due to Ohmic losses is becoming a bottleneck for both speed and power-consumption scaling. Using photons as information carriers is a promising alternative. Here, the authors reveal a new all-optical computing framework to realize ultrafast and ultralow-energy-consumption all-optical computing based on convolutional neural networks. The device is constructed from cascaded silicon Y-shaped waveguides with side-coupled silicon waveguide segments (weight modulators) to enable complete phase and amplitude control in each waveguide branch. The generic device concept can be used for equation solving, multifunctional logic operations, as well as other mathematical operations. Multiple computing functions, including transcendental equation solvers, multifarious logic gate operators, and half-adders, were demonstrated to validate the all-optical computing performances. The time of flight of light through the network structure corresponds to an ultrafast computing time of the order of several picoseconds with an ultralow energy consumption of dozens of femtojoules per bit. The approach can be further expanded to fulfill other complex computing tasks based on non-von Neumann architectures, thus paving a new way for on-chip all-optical computing. (Opto-Electronic Advances, November 2021, https://www.oejournal.org/article/doi/10.29026/oea.2021.200060)

This column provides abstracts from recent industry conferences and company white papers. Our goal is to provide an added opportunity for readers to keep abreast of technology and business trends.