Facile synthesis of α-Fe2O3/ZnO core-shell nanowires for enhanced H2S sensing.

• Heterostructured α-Fe 2 O 3 /ZnO core-shell NWs with precisely controlled shell thickness were synthesized by ALD. • The NWs structured MEMS gas sensors with 20 nm ZnO shell layer exhibited enhanced sensitive and selective H 2 S detection. • The maximum response of the α-Fe 2 O 3 /ZnO core-shell NWs gas sensor to 5 ppm H 2 S is 5.98 at an operating temperature of 250 °C. The α-Fe 2 O 3 /ZnO core-shell nanowires (NWs) on micro-electro-mechanical system structure were prepared for hydrogen sulfide (H 2 S) gas sensing. Core α-Fe 2 O 3 NWs were prepared by thermal oxidation and the ZnO shell layer was coated by atomic layer deposition, respectively. The diameter of the obtained α-Fe 2 O 3 /ZnO core-shell NWs increases uniformly with the increase of ZnO shell thickness. When the operating temperature is 250 °C, the maximum response of the α-Fe 2 O 3 /ZnO core-shell NWs gas sensor to 5 ppm H 2 S is 5.98, which is about five times of pure α-Fe 2 O 3 NWs gas sensor (∼1.1). Moreover, α-Fe 2 O 3 /ZnO core-shell NWs-based gas sensors showed good selectivity, response, and recovery properties to H 2 S. The improvement of gas response of core-shell NWs is due to the slender α-Fe 2 O 3 /ZnO core-shell NWs and the appropriate energy band structure between ZnO and α-Fe 2 O 3. Thus, the proposed α-Fe 2 O 3 /ZnO core-shell NWs will be one of ideal sensitive materials for H 2 S high-performance sensor. [ABSTRACT FROM AUTHOR]