Improved gas sensing and dielectric properties of Fe doped hydroxyapatite thick films: Effect of molar concentrations

• We report improved gas sensing and dielectric characteristics of Fe ion exchanged HAp films.
• Fe doped HAp film shows maximum gas response at relatively lower temperature.
• Response & gas uptake capacity of sensors is improved for appropriate amount of Fe ions in HAp matrix.
• Fe-HAp films exhibit remarkable improvement in dielectric properties compared to pure HAp.
• Fe doped HAp films show significant improvement in gas sensing as well as in dielectric properties.

In the present work Fe doped hydroxyapatite (Fe-HAp) thick films has been successfully utilized to improve the gas sensing as well as its dielectric properties. Initially, HAp nano powder is synthesized by chemical precipitation process and later on Fe ions are doped in HAp by ion exchange process. Structural and morphological modifications are observed by means of X-ray diffraction and scanning electron microscopy analysis. The sensing parameters such as operating temperature, response/recovery time and gas uptake capacity are experimentally determined. The Fe-HAp (0.05 M) film shows improved CO and CO2 gas sensing capacity at lower operating temperature compared to pure HAp. Moreover, variation of dielectric constant and dielectric loss for pure and Fe-HAp thick films are studied as a function of frequency in the range of 10 Hz–1 MHz. The study reveals that Fe doped HAp thick films improve the sensing and dielectric characteristics as compared to pure HAp.

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