Engineering topics
Publications and source records attributed to Mao, Elizabeth.
This report is intended to provide a comprehensive overview of information and communications technologies [ICT], including ICT infrastructure, electronics manufacturing, and smart manufacturing.
We report high temperature surface acoustic wave (SAW) gas sensors with conducting sensing layers require tuning of the sheet conductivity for optimal response. Conducting metal oxides are attractive sensing materials for their tunable electronic properties and high thermal stability, amongst others. Here, we have investigated the application of indium oxide (IO) and indium tin oxide (ITO) films on langasite (LGS)-based SAW reflective delay line sensor devices for monitoring hydrogen at 350 °C. Specifically, we modeled the effect of the IO and ITO sensing layer thickness on the wave velocity, attenuation, and effective electromechanical coefficient. This was followed by an experimental demonstration of tuning of the ITO film sheet conductivity by controlling the dopant concentration and yielding an improvement in the sensor sensitivity. The current study provides a pathway towards the development of conductivity-based sensing layers for high temperature SAW gas sensors with improved sensitivity.
Information and communication technology (ICT) has been critical to the emergence of a new Internet-of-Things (IoT) era, as a rapidly increasing number and variety of IoT electronic devices in a wide range of end-use sectors require massive data communication in terms of volume, velocity/speed, and variety. Additionally, semiconductor technology advancements have played a key role in ICT and unlike the past ICT energy footprint analysis, which focused on the final electronic product, an attempt has been made to examine the global energy impacts for the period 2016–2025 based on the market forecasts of three major IoT IC types, i.e., sensors and actuators, connectivity, and processor ICs distributed among four major IoT device components.Total global IoT semiconductor primary energy demand is projected to increase from 2 EJ in 2016 to 35 EJ by 2025, resulting mainly from a substantial projected increase energy needed in the manufacturing of ICs, with growth in the use of sensors and energy-intensive next fab generation manufacturing. Unlike the trend in manufacturing energy, total global operational energy use is projected to decrease significantly with the development of smaller transistor size, low-power devices, and faster wireless data communication technology. Total operational energy is projected to significantly decrease from 118 TWh/year (1,2 EJ/year) to less than 1 TWh/year (0.003 EJ/year) in spite of a significantly higher anticipated growth in its market size during the 2016–2025 forecast period. Its annual share of total primary energy use is projected to reach an insignificant level of 0.01% by the end of 2025, consistent with the past limited electronic product life cycle analyses besides the analysis focus here limited to ICs in IoT devices.
<p style="text-align: justify;"><span style="font-family: Arial; font-size: 10pt;">• </span><span style="color: black; font-family: Arial; font-size: 10pt;">SAW reflective delay line devices were designed and successfully fabricated on Langasite by patterning platinum electrodes.</span><p style="text-align: justify;"><span style="font-family: Arial; font-size: 10pt;">• </span><span style="color: black; font-family: Arial; font-size: 10pt;">Fabricated devices successfully tested up to 500°C for temperature sensing applications.</span><p style="text-align: justify;"><span style="font-family: Arial; font-size: 10pt;">• </span><span style="color: black; font-family: Arial; font-size: 10pt;">Indium oxide (IO) and indium tin oxide (ITO) sensing layers were developed on the SAW devices using sputtering and sol-gel method.</span><p style="text-align: justify;"><span style="font-family: Arial; font-size: 10pt;">• </span><span style="color: black; font-family: Arial; font-size: 10pt;">IO- and ITO-functionalized langasite SAW reflective delay line devices were used for sensing H2 and O2 at 350°C. </span><br>