Machine Learning Driven Channel Thickness Optimization in Dual‐Layer Oxide Thin‐Film Transistors for Advanced Electrical Performance

Abstract Machine learning (ML) provides temporal advantage and performance improvement in practical electronic device design by adaptive learning. Herein, Bayesian optimization (BO) is successfully applied to the design of optimal dual‐layer oxide semiconductor thin film transistors (OS TFTs). This approach effectively manages the complex correlation and interdependency between two oxide semiconductor layers, resulting in the efficient design of experiment (DoE) and reducing the trial‐and‐error. Considering field effect mobility () and threshold voltage (Vth) simultaneously, the dual‐layer structure designed by the BO model allows to produce OS TFTs with remarkable electrical performance while significantly saving an amount of experimental trial (only 15 data sets are required). The optimized dual‐layer OS TFTs achieve the enhanced field effect mobility of 36.1 cm2 V−1 s−1 and show good stability under bias stress with negligible difference in its threshold voltage compared to conventional IGZO TFTs. Moreover, the BO algorithm is successfully customized to the individual preferences by applying the weight factors assigned to both field effect mobility () and threshold voltage (Vth)

Biocompatible Direct Deposition of Functionalized Nanoparticles using Shrinking Surface Plasmonic Bubble

Functionalized nanoparticles (NPs) are the foundation of diverse applications, such as photonics, composites, energy conversion, and especially biosensors. In many biosensing applications, concentrating the higher density of NPs in the smaller spot without deteriorating biofunctions is usually an inevitable step to improve the detection limit, which remains to be a challenge. In this work, we demonstrate biocompatible deposition of functionalized NPs to an optically transparent surface using shrinking surface plasmonic bubbles. Leveraging the shrinking bubble can enable to mitigate any potential biomolecules degradation by strong photothermal effect, which has been a big obstacle of bridging plasmonic bubbles with biomolecules. The deposited NPs are closely packed in a micro-sized spot (as small as 3 μm), and the functional molecules are able to survive the process as verified by their strong fluorescence signals. We elucidate that the contracting contact line of the shrinking bubble forces the NPs captured by the contact line to a highly concentrated island. Such a shrinking surface bubble deposition (SSBD) is low temperature in nature as no heat is added during the process. Using a hairpin DNA-functionalized gold NP suspension as a model system, SSBD is shown to enable much stronger fluorescence signal compared to the optical pressure deposition and the conventional steady thermal bubble contact line deposition. The demonstrated SSBD technique capable of directly depositing functionalized NPs may benefit a wide range of applications, such as the manufacturing of multiplex biosensors.</p

Nanostructures Significantly Enhance Thermal Transport across Solid Interfaces

The efficiency of thermal transport across solid interfaces presents large challenges for modern technologies such as thermal management of electronics. In this paper, we report the first demonstration of significant enhancement of thermal transport across solid interfaces by introducing interfacial nanostructures. Analogous to fins that have been used for macroscopic heat transfer enhancement in heat exchangers, the nanopillar arrays patterned at the interface help interfacial thermal transport by the enlarged effective contact area. Such a benefit depends on the geometry of nanopillar arrays (e.g., pillar height and spacing), and a thermal boundary conductance enhancement by as much as ∼88% has been measured using the time-domain thermoreflectance technique. Theoretical analysis combined with low-temperature experiments further indicates that phonons with low frequency are less influenced by the interfacial nanostructures due to their large transmissivity, but the benefit of the nanostructure is fully developed at room temperature where higher frequency phonons dominate interfacial thermal transport. The findings from this work can potentially be generalized to benefit real applications such as the thermal management of electronics