Comparative study on gas sensing properties of rare earth (Tb, Dy and Er) doped ZnO sensor

Zinc oxide and rare earth (Tb, Dy and Er) doped zinc oxide has been synthesized chemically by facile and cost effective co-precipitation method. Effect of dopant on structural, optical and morphological properties of ZnO has been studied by using various characterization techniques. Synthesized powder samples were deposited as thick films on alumina substrate and their gas sensing characteristics have been investigated for various gases at different operable temperatures. Doped ZnO samples have exhibited significant enhancement in sensor response to ethanol and reduction in optimum operable temperature as well. The study also revealed temperature dependent selectivity behavior of Tb and Er doped ZnO sensors towards ethanol and acetone. Significant increase in the gas sensor response of doped samples has been corroborated to their high surface basicity, increased surface area, morphological changes and oxygen vacancies present.