Heated air sensitivity of Zn1- x Cd x O films

In this work, we have investigated the heat sensitivity of a Zn_1-xCd_xO (x = 0.03–1) films obtained by spray-pyrolysis under the influence of atmospheric air, considering the substrate type, air temperature, and Cd concentration. We found a transition in the electrical conductivity behavior when x is around 0.55 (55 at.% Cd). This transition is related to the structural phase transition that also occurs close to this concentration. It has been proved that the thermal response amplitude is directly related to the surface morphology of films, which depends on the substrate type and the Cd concentration. We found that thermal sensitivity and signal quality are higher for samples grown on top of Si substrates. The conductivity changes are reproducible over a strategic temperature range (50–100 °C), making the films available for practical applications.