Chemisorption and sensitivity at semiconductor sensors revisited

MIRABELLA, D.A.; RESASCO, D.E.; ALDAO, C.M.; BUONO, C.

SENSORS AND ACTUATORS B-CHEMICAL

ELSEVIER SCIENCE SA

Año: 2019 vol. 285 p. 232 - 239

0925-4005

In this work we derived the adsorption isotherms for non-dissociative and dissociative chemisorption of oxygen on a semiconductor surface. We extended the Wolkenstein theory for dissociative chemisorption and re-examined the basis that led to currently accepted formalisms in the literature. In particular, we correctly incorporated dissociative chemisorption as a second-order reaction. We determined band bendings and adsorbate coverages for different gas pressure and doping for a typical metal-oxide used in gas sensing. Finally, consequences for the sensor conductivity and sensitivity are discussed.