To prepare a novel Bio sensor for ethanol vapour detection with higher sensitivity. In this Zn(Mn)/ZnO inverted core shell structure is doped in starch. Add a noble metal foe the better response. After this making thin films and determine the thickness of a thin films. Dielectric constant is determined by using the LCR meter. The characterization is done by using XRD, SEM, and the sensing properties of ethanol sensor are based on the resistance-based sensing.