Transfer of preheat-treated SnO2 via a sacrificial bridge-type ZnO layer for ethanol gas sensor

•Preheating SnO2 before transferring can eliminate severe damage to sensor devices.•A scrificial bridge-type ZnO hydrothermally grown can block the penentration of SnO2 nanoparticles.•The capillary rise of acidic solution can be induced through voids between the ZnO NRs posts.•Transferred SnO2 sensors showed a response time of 52s at ethanol gas of 20ppm.•Even at 2ppm the transferred SnO2 sensor exhibited square-shaped sensing behavior.