A team of researchers from University of Houston, in Texas (USA), developed a new sensor capable of operating at temperatures up to 900 ° C. This sensor was fabricated from ultra-wide bandgap AlN monocrystalline thin films.
The University of Houston research team previously developed a III-N piezoelectric pressure sensor using single-crystal gallium nitride or GaN thin films for harsh environment applications. However, the sensitivity of the sensor drops at temperatures above 350 °C, which is higher than that of conventional lead zirconate titanate (PZT) transducers, but only marginally.
The team believes the lower sensitivity is because the bandgap, which is the minimum energy needed to excite an electron and provide electrical conductivity, was not wide enough. To test the hypothesis, they developed a sensor with aluminum nitride, or AlN.
higher temperature range
After the tests, the researchers verified that with the new material, the sensor could operate at about 1,000 degrees Celsius. While AlN and GaN both have unique properties that are ideal for use in sensors for harsh environments, AlN offers a wider bandgap and higher temperature range.
However, the team had to contend with technical challenges related to the synthesis and fabrication of high-quality flexible AlN thin films. The next steps in the research are based on testing the sensor in various real-world scenarios.
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