Micro‐module Peltier elaborated by flash technique and used as a humidity sensor

In this work an original humidity sensor is described. It is based on the study of Seebeck voltage evolution during the water evaporation of a micro‐module Peltier (MMP). The measurement principle is to detect (after cooling) the small temperature decrease created when total water evaporation occurs over the MMP. All the active thin layers of the sensor are made from (Bi₂Te₃)_0.9(Bi₂Se₃)_0.1 (N) films and (Bi₂Te₃)_0.25(Sb₂Te₃)_0.75 (P) films flash evaporated. Experimental measures were performed in a climatic chamber for several values of relative humidity (50 to 90 per cent). The phenomenon (evaporation) appears after a delay time τ. This delay time is the response time of the sensor. Therefore it is possible to draw the evaporation delay time as a function of relative humidity.