All-Inorganic Metal Oxide-Based p-n Heterojunction Ternary-State Transistors.

Ternary logic has been proposed as a type of many-valued logic system to overcome the limitations of integration density and energy efficiency in the current complementary metal-oxide-semiconductor (CMOS) technology. In detail, p-n heterojunction transistors with ternary-state switching characteristics can implement ternary logic structures. However, most research on p-n heterojunction ternary-state transistors (TSTs) has focused on organic or 2D materials, which face significant challenges in meeting the demands of current CMOS technology.

Simultaneous Improvement of Multiple Electrical Characteristics in Ultrathin a-IGZO TFTs Using Machine Learning Optimization.

While IGZO is emerging as a promising channel material to address the scaling limitations of conventional silicon-based DRAM, its application in next-generation 3D DRAM requires further advancements in achieving ultrathin structures and excellent performance tailored to DRAM characteristics. Specifically, optimizing process variables is essential for enhancing mobility in ultrathin structures, where mobility tends to degrade significantly, while maintaining a constant threshold voltage, a task that is both experimentally intensive and resource-demanding. This study employed multi-objective Bayesian optimization (MOBO) machine learning (ML) to simultaneously optimize multiple electrical objectives, aiming to achieve high mobility and a near-zero threshold voltage for ultrathin IGZO thin-film transistors (TFTs) under complex sputtering conditions, involving a wide range of possible combinations of Ar gas flow, sputtering power, and working pressure.

Wet Pretreatment-Induced Modification of Cu(In,Ga)Se/Cd-Free ZnTiO Buffer Interface.

We report a novel Cd-free ZnTiO buffer layer deposited by atomic layer deposition for Cu(In,Ga)Se (CIGS) solar cells. Wet pretreatments of the CIGS absorbers with NHOH, HO, and/or aqueous solution of Cd ions were explored to improve the quality of the CIGS/ZnTiO interface, and their effects on the chemical state of the absorber and the final performance of Cd-free CIGS devices were investigated. X-ray photoelectron spectroscopy (XPS) analysis revealed that the aqueous solution etched away sodium compounds accumulated on the CIGS surface, which was found to be detrimental for solar cell operation.

Estimation of sleep posture using a patch-type accelerometer based device.

In this study, we developed a sleep posture estimation algorithm using 3-axis accelerometer signals measured from a patch-type sensor. Firstly, we inspected the characteristics of accelerometer signals for different sleep postures. Based on the results, we established decision rules to estimate 5 postures containing supine, left, right lateral, prone postures, and non-sleep postures such as sitting and standing.

Sleep/wake estimation using only anterior tibialis electromyography data.

Background: In sleep efficiency monitoring system, actigraphy is the simplest and most commonly used device. However, low specificity to wakefulness of actigraphy was revealed in previous studies. In this study, we assumed that sleep/wake estimation using actigraphy and electromyography (EMG) signals would show different patterns.