Piezoelectric Sensors Operating at Very High Temperatures and in Extreme Environments Made of Flexible Ultrawide-Bandgap Single-Crystalline AlN Thin Films

Nam In Kim, Miad Yarali, Mina Moradnia, Muhammad Aqib, Che Hao Liao, Feras AlQatari, Mingtao Nong, Xiaohang Li, Jae Hyun Ryou*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Extreme environments are often faced in energy, transportation, aerospace, and defense applications and pose a technical challenge in sensing. Piezoelectric sensor based on single-crystalline AlN transducers is developed to address this challenge. The pressure sensor shows high sensitivities of 0.4–0.5 mV per psi up to 900 °C and output voltages from 73.3 to 143.2 mV for input gas pressure range of 50 to 200 psi at 800 °C. The sensitivity and output voltage also exhibit the dependence on temperature due to two origins. A decrease in elastic modulus (Young's modulus) of the diaphragm slightly enhances the sensitivity and the generation of free carriers degrades the voltage output beyond 800 °C, which also matches with theoretical estimation. The performance characteristics of the sensor are also compared with polycrystalline AlN and single-crystalline GaN thin films to investigate the importance of single crystallinity on the piezoelectric effect and bandgap energy-related free carrier generation in piezoelectric devices for high-temperature operation. The operation of the sensor at 900 °C is amongst the highest for pressure sensors and the inherent properties of AlN including chemical and thermal stability and radiation resistance indicate this approach offers a new solution for sensing in extreme environments.

Original languageEnglish (US)
Article number2212538
JournalAdvanced Functional Materials
Volume33
Issue number10
DOIs
StatePublished - Mar 2 2023

Bibliographical note

Publisher Copyright:
© 2022 Wiley-VCH GmbH.

Keywords

  • flexible electronics
  • harsh environments
  • piezoelectric sensors
  • ultrawide-bandgap single-crystalline films

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • General Chemistry
  • Biomaterials
  • General Materials Science
  • Condensed Matter Physics
  • Electrochemistry

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