Synthesis, Characterization, and Humidity Detection Properties of Nb₂O₅ Nanorods and SnO₂/Nb₂O₅ Heterostructures

Nanostructured metal oxide semiconductors are ideally suited for their integration in different devices due to their high thermal and mechanical stability, unique electronic characteristics, and low-cost fabrication. The modification of their surface allows the design of heterostructures with novel properties. In this work, we have synthesized single-crystalline niobium pentoxide (Nb 2 O 5 ) nanorods and niobium-pentoxide-coated tin oxide (Nb 2 O 5 /SnO 2 ) heterostructures by chemical vapor deposition. HR-TEM analysis and computer simulation studies showed the low density of defects and high crystallinity of the Nb 2 O 5 nanorods, which exhibited high sensitivity toward humidity at low temperatures (60 °C). The fabrication of SnO 2 /Nb 2 O 5 core–shell heterostructures combines the high sensitivity of Nb 2 O 5 shell toward moisture with the good electrical conductivity of SnO 2 . The growth of the nanoscopic Nb 2 O 5 overlayer on SnO 2 nanowires introduces defects in the structure, which influence the electronic properties of the material and enable the design of more efficient humidity sensors.