Performance demonstration of cavity-free planar multi-stage bileg and unileg silicon-nanowire thermoelectric generators.

A Thermoelectric (TE) generator is expected to play an important role in the operation of tiny-watt capable wireless power supply devices by converting the waste heat energy into electrical energy. This work is the demonstration of planar cavity-free multi-stage n-type unileg- and bileg Si-nanowire (Si-NW) TE generators. The result shows that the output power of the multi-stage bileg-TE generator increases linearly with increasing the stage number, whereas the rate of increase of the multi-stage unileg-TE generator power output tends to decrease as the stage number increases. Although the power of the multi-stage bileg-TE generator fabricated in this work was smaller than that of the multi-stage unileg-TE generator due to the large internal resistance of p-type elements, however, the improved linearity of the bileg-TE generator than the unileg-TE generator indicates the potential advantage of the multi-stage bileg-TE generator for the large-scale integration.

Effect of Electrolytic Medium on the Electrochemical Reduction of Graphene Oxide on Si(111) as Probed by XPS

The wafer-scale integration of graphene is of great importance in view of its numerous applications proposed or underway. A good graphene–silicon interface requires the fine control of several parameters and may turn into a high-cost material, suitable for the most advanced applications. Procedures that can be of great use for a wide range of applications are already available, but others are to be found, in order to modulate the offer of different types of materials, at different levels of sophistication and use. We have been exploring different electrochemical approaches over the last 5 years, starting from graphene oxide and resulting in graphene deposited on silicon-oriented surfaces, with the aim of understanding the reactions leading to the re-establishment of the graphene network. Here, we report how a proper choice of both the chemical environment and electrochemical conditions can lead to a more controlled and tunable graphene–Si(111) interface. This can also lead to a deeper understanding of the electrochemical reactions involved in the evolution of graphene oxide to graphene under electrochemical reduction. Results from XPS, the most suitable tool to follow the presence and fate of functional groups at the graphene surface, are reported, together with electrochemical and Raman findings.

Unbalanced-Tests to the Improvement of Yield and Quality

An integrated-circuit testing model (DITM) is used to describe various factors that affect test yield during a test process. We used a probability distribution model to evaluate test yield and quality and introduced a threshold test and a guardband test. As a result of the development speed of the semiconductor manufacturing industry in the future being unpredictable, we use electrical properties of existing products and the current manufacturing technology to estimate future product-distribution trends. In the development of very-large-scale integration (VLSI) testing, the progress of testing technology is very slow. To improve product testing yield and quality, we change the test method and propose an unbalanced-test method, leading to improvements in test results. The calculation using our proposed model and data estimated by the product published by the IEEE International Roadmap for Devices and Systems (IRDS, 2017) proves that the proposed unbalanced-test method can greatly improve test yield and quality and achieve the goal of high-quality, near-zero-defect products.

Wafer-scale integration of stretchable semiconducting polymer microstructures via capillary gradient

Organic semiconducting polymers have opened a new paradigm for soft electronics due to their intrinsic flexibility and solution processibility. However, the contradiction between the mechanical stretchability and electronic performances restricts the implementation of high-mobility polymers with rigid molecular backbone in deformable devices. Here, we report the realization of high mobility and stretchability on curvilinear polymer microstructures fabricated by capillary-gradient assembly method. Curvilinear polymer microstructure arrays are fabricated with highly ordered molecular packing, controllable pattern, and wafer-scale homogeneity, leading to hole mobilities of 4.3 and 2.6 cm2 V−1 s−1 under zero and 100% strain, respectively. Fully stretchable field-effect transistors and logic circuits can be integrated in solution process. Long-range homogeneity is demonstrated with the narrow distribution of height, width, mobility, on-off ratio and threshold voltage across a four-inch wafer. This solution-assembly method provides a platform for wafer-scale and reproducible integration of high-performance soft electronic devices and circuits based on organic semiconductors.

Systematic review of centrifugal valving based on digital twin modeling towards highly integrated lab-on-a-disc systems

Current, application-driven trends towards larger-scale integration (LSI) of microfluidic systems for comprehensive assay automation and multiplexing pose significant technological and economical challenges to developers. By virtue of their intrinsic capability for powerful sample preparation, centrifugal systems have attracted significant interest in academia and business since the early 1990s. This review models common, rotationally controlled valving schemes at the heart of such “Lab-on-a-Disc” (LoaD) platforms to predict critical spin rates and reliability of flow control which mainly depend on geometries, location and liquid volumes to be processed, and their experimental tolerances. In absence of larger-scale manufacturing facilities during product development, the method presented here facilitates efficient simulation tools for virtual prototyping and characterization and algorithmic design optimization according to key performance metrics. This virtual in silico approach thus significantly accelerates, de-risks and lowers costs along the critical advancement from idea, layout, fluidic testing, bioanalytical validation, and scale-up to commercial mass manufacture.