Enhanced ethanol sensing performance using Co3O4–ZnSnO3 arrays prepared on alumina substrates.

In this work, novel n-type heterostructures of ZnSnO 3 modified p-type Co 3 O 4 (Co 3 O 4 –ZnSnO 3) nanowire arrays were fabricated in-situ on flat alumina substrates via a simple hydrothermal method without seed layers. SEM and TEM characterizations revealed that the Co 3 O 4 nanowire arrays were fully covered by ZnSnO 3 nanosheets. The gas-sensing measurement revealed that the Co 3 O 4 –ZnSnO 3 composite arrays showed the highest response 5.57 (R g /R a) towards ethanol, which was 2.04 times higher than that of Co 3 O 4 nanowire arrays (R g /R a = 2.73). Meanwhile, the enhanced sensing mechanism of Co 3 O 4 –ZnSnO 3 composite arrays was also discussed, which could be explained by the special heterojunction structure arrays that offered an additional modulation in resistance. Our studies shed a new light to design p-n heterostructure arrays in-situ sensing device by a facile method. Moreover, the as-designed Co 3 O 4 –ZnSnO 3 composite arrays have potential application for fabricating high performance ethanol sensors. • Co 3 O 4 –ZnSnO 3 arrays were fabricated in-situ on alumina substrates without seed layers. • The Co 3 O 4 –ZnSnO 3 arrays showed the highest response towards ethanol than pristine Co 3 O 4. • The enhanced gas-sensing mechanism was ascribed to the p-n heterojunction structures. [ABSTRACT FROM AUTHOR]