Low-power-consumption gas sensors are crucial for diverse applications, including environmental monitoring and portable Internet of Things (IoT) systems. However, the desorption and adsorption characteristics of conventional metal oxide-based gas sensors require supplementary equipment, such as heaters, which is not optimal for low-power IoT monitoring systems. Memristor-based sensors (gasistors) have been investigated as innovative gas sensors owing to their advantages, including high response, low power consumption, and room-temperature (RT) operation. Based on IGZO, the proposed isopropanol alcohol (IPA) gas sensor demonstrates a detection speed of 105 s and a high response of 55.15 for 50 ppm of IPA gas at RT. Moreover, rapid recovery to the initial state was achievable in 50 μs using pulsed voltage and without gas purging. Finally, a low-power circuit module was integrated for wireless signal transmission and processing to ensure IoT compatibility. The stability of sensing results from gasistors based on IGZO has been demonstrated, even when integrated into IoT systems. This enables energy-efficient gas analysis and real-time monitoring at ~0.34 mW, supporting recovery via pulse bias. This research offers practical insights into IoT gas detection, presenting a wireless sensing system for sensitive, low-powered sensors.

Antireflection coatings (ARCs) with an indium thin oxide (ITO) layer on silicon heterojunction solar cells (SHJ) have garnered significant attention, which is due to their potential for increasing current density (J_sc) and enhancing reliability. We propose an additional tungsten trioxide (WO₃) layer on the ITO/Si structure in this paper in order to raise the J_sc and demonstrate the influence on the SHJ solar cell. First, we simulate the J_sc characteristics for the proposed WO₃/ITO/Si structure in order to analyze J_sc depending on the thickness of WO₃ using an OPAL 2 simulator. As a result, the OPAL 2 simulation shows an increase in J_sc of 0.65 mA/cm² after the 19 nm WO₃ deposition on ITO with a doping concentration of 6.1 × 10²⁰/cm². We then fabricate the proposed samples and observe an improved efficiency of 0.5% with an increased J_sc of 0.75 mA/cm² when using a 20 nm thick WO₃ layer on the SHJ solar cell. The results indicate that the WO₃ layer can be a candidate to improve the efficiency of SHJ solar cells with a low fabrication cost.