In industries such as aerospace, transportation, energy, and defense, sensors are vital to measuring and monitoring various factors under harsh conditions to guarantee human safety and the integrity of mechanical systems. However, these environments often require highly sensitive, reliable, and durable sensors.
Development of a High-Temperature Sensor
Researchers at the University of Houston have developed a new sensor that can withstand temperatures as high as 900 degrees Celsius or 1,650 degrees Fahrenheit, similar to the temperature of mafic volcanic lava, the hottest type of lava on earth. The sensor, made of flexible ultrawide-bandgap single-crystalline aluminum nitride (AlN) thin films, was proven to work in extreme environments, which is necessary for the efficiency, maintenance, and integrity of various applications.
Challenges and Findings
The UH research team had previously developed III-N piezoelectric pressure sensors using single-crystalline gallium nitride (GaN) thin films for harsh-environment applications. However, the sensitivity of the sensor decreased at temperatures higher than 350 degrees Celsius.
The researchers believed that the decrease in sensitivity was due to the bandgap, the minimum energy required to excite an electron and supply electrical conductivity, not being wide enough. To test the hypothesis, they developed a sensor with AlN.
Although both AlN and GaN have unique and excellent properties suitable for use in sensors for extreme environments, the researchers found that AlN offered a wider bandgap and an even higher temperature range. However, the team faced technical challenges involving the synthesis and fabrication of the high-quality, flexible thin-film AlN.
Potential Applications
Now that the researchers have successfully demonstrated the potential of the high-temperature piezoelectric sensors with AlN, they plan to test it further in real-world harsh conditions. The team intends to use the sensor in nuclear plants for neutron exposure and hydrogen storage to test under high pressure. AlN sensors can operate in neutron-exposed atmospheres and at very high-pressure ranges thanks to its stable material properties.
The flexibility of the sensor offers additional advantages that will make it useful for future applications in the form of wearable sensors in personal health care monitoring products and for use in precise-sensing soft robotics.
The researchers anticipate that their sensor will be commercially viable in the future, but they cannot specify a date. Nevertheless, they believe that it is their responsibility as engineers to make it happen as soon as possible. The development of this high-temperature sensor is a significant step forward in the creation of highly sensitive, reliable, and durable sensors that can tolerate extreme environments. The potential uses of these sensors are vast, ranging from personal health care monitoring to nuclear plants.
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