Extended Hückel Theory for Quantum Transport in Magnetic Tunnel Junctions

Abstract-Spin-resolved conductivities in magnetic tunnel junctions are calculated using a semiempirical tight-binding model and non-equilibrium Green's functions. The performance of half-metallic electrodes is studied by comparing conventional Fe-MgO-Fe structures to Co2FeAl-MgO-Co2FeAl structures. The results show higher tunneling magnetoresistance and resistancearea product for Co2FeAl devices across a wide bias range

The International Natural Product Sciences Taskforce (INPST) and the power of Twitter networking exemplified through #INPST hashtag analysis

Background: The development of digital technologies and the evolution of open innovation approaches have enabled the creation of diverse virtual organizations and enterprises coordinating their activities primarily online. The open innovation platform titled "International Natural Product Sciences Taskforce" (INPST) was established in 2018, to bring together in collaborative environment individuals and organizations interested in natural product scientific research, and to empower their interactions by using digital communication tools. Methods: In this work, we present a general overview of INPST activities and showcase the specific use of Twitter as a powerful networking tool that was used to host a one-week "2021 INPST Twitter Networking Event" (spanning from 31st May 2021 to 6th June 2021) based on the application of the Twitter hashtag #INPST. Results and Conclusion: The use of this hashtag during the networking event period was analyzed with Symplur Signals (https://www.symplur.com/), revealing a total of 6,036 tweets, shared by 686 users, which generated a total of 65,004,773 impressions (views of the respective tweets). This networking event's achieved high visibility and participation rate showcases a convincing example of how this social media platform can be used as a highly effective tool to host virtual Twitter-based international biomedical research events

Design and fabrication of an indirectly heated electrothermal actuator

Abstract: This paper describes the fabrication and experimental characterization of bent-beam (V-shaped) electrothermal actuators for use in microelectromechanical systems (MEMS). The actuators are of the polymer SU-8, a negative photoresist notable for its suitably large coefficient of thermal expansion, and are fabricated on FR-4 substrate, a typical printed circuit board material that is better matched to expanding SU-8 than the more commonly used silicon substrates. The fabrication technology used is ultraviolet lithography and electroplating, known by its German acronym UV LIG (Lithographie, Galvanoformung). These actuators have beams 6 to 10 mm across with widths of 200 to 400 µm and heights of roughly 800 µm for the structural SU-8 and 7 µm for the metal heating structures. The focus of this work is on the effects of placing a nickel heating structure on the underside of the SU-8 beam as well as the fabrication challenges. This placement allows for electrical contacts to lie on the substrate and removes the difficulty of wire bonding. The resistance of this heating structure is measured with respect to geometry and the results suggest that surface roughness in the Ni due to the use of FR-4 substrate measurably affects the electrical resistance at film thicknesses less than 7 µm. Typical resistances of the nickel heating structures were measured to be roughly 3 - 5 Ohm for one geometry used and 0.4 - 0.8 Ohm for the other. Displacements of over 100 µm are achieved by the actuators at a power of 400 to 500 mW. The performance of this configuration is compared to the typical thin film on top heating method and shows that it is less energy efficient due to increased heat loss, creating a trade-off of simpler electrical connections but higher power consumption

Thermal Radiation Measurements of Graphene for Temperature Extraction

Graphene is a two-dimensional carbon crystal arranged in a honeycomb lattice. Its excellent electronic properties and planar geometry make it a viable candidate for nanoelectronic applications. In this study, large-area (0.25 mm2) graphene grown by chemical vapor deposition on a 90 nm SiO2 substrate was put under high bias. The resulting thermal radiation was measured in different infrared wavelength ranges. By comparing the amount of radiation in various bands, an approximate temperature of the emitting source can be determined due to the uniqueness of the blackbody profile at each temperature. Integrated radiation at different biases may also be compared to determine temperature if one temperature is known. These extracted temperatures are compared with the expected temperature calculated using a model based on thermal resistances.unpublishednot peer reviewedU of I OnlyUndergraduate senior thesis not recommended for open acces

Limits of Specific Contact Resistivity to Si, Ge and III-V Semiconductors Using Interfacial Layers

Abstract-Specific contact resistivities of source/drain contacts employing interfacial layers are calculated with simulations of tunneling transport. Fermi level depinning, dipoles, and other techniques for barrier lowering are explored. Interfacial materials with the potential to meet future contact resistivity requirements are identified for silicon and high-mobility alternatives

Improved Contacts to MoS₂ Transistors by Ultra-High Vacuum Metal Deposition

The scaling of transistors to sub-10 nm dimensions is strongly limited by their contact resistance (<i>R</i>_C). Here we present a systematic study of scaling MoS₂ devices and contacts with varying electrode metals and controlled deposition conditions, over a wide range of temperatures (80 to 500 K), carrier densities (10¹² to 10¹³ cm^–2), and contact dimensions (20 to 500 nm). We uncover that Au deposited in ultra-high vacuum (∼10^–9 Torr) yields three times lower <i>R</i>_C than under normal conditions, reaching 740 Ω·μm and specific contact resistivity 3 × 10^–7 Ω·cm², stable for over four months. Modeling reveals separate <i>R</i>_C contributions from the Schottky barrier and the series access resistance, providing key insights on how to further improve scaling of MoS₂ contacts and transistor dimensions. The contact transfer length is ∼35 nm at 300 K, which is verified experimentally using devices with 20 nm contacts and 70 nm contact pitch (CP), equivalent to the “14 nm” technology node

The International Natural Product Sciences Taskforce (INPST) and the power of Twitter networking exemplified through #INPST hashtag analysis

International audienceBackground: The development of digital technologies and the evolution of open innovation approaches have enabled the creation of diverse virtual organizations and enterprises coordinating their activities primarily online. The open innovation platform titled "International Natural Product Sciences Taskforce" (INPST) was established in 2018, to bring together in collaborative environment individuals and organizations interested in natural product scientific research, and to empower their interactions by using digital communication tools. Methods: In this work, we present a general overview of INPST activities and showcase the specific use of Twitter as a powerful networking tool that was used to host a one-week "2021 INPST Twitter Networking Event" (spanning from 31st May 2021 to 6th June 2021) based on the application of the Twitter hashtag #INPST. Results and Conclusion: The use of this hashtag during the networking event period was analyzed with Symplur Signals (https://www.symplur.com/), revealing a total of 6,036 tweets, shared by 686 users, which generated a total of 65,004,773 impressions (views of the respective tweets). This networking event's achieved high visibility and participation rate showcases a convincing example of how this social media platform can be used as a highly effective tool to host virtual Twitter-based international biomedical research events