10 nm Scale WO3/CuO Heterojunction Nanochannel for an Ultra-sensitive Chemical Sensor

The fabrication of p–n heterostructures of a metal oxide semiconductor (MOS) showed that a large amount of heterojunction interfaces is one of the key issues in MOS gas sensor research, since it could significantly enhance the sensing performance. Despite considerable progress in this area, fabrication of an ideal p–n heterojunction sensing channel has been challenging because of morphological limitations of synthetic methods in the conventional bottom-up fabrication based on precursor reductions. In this study, a 10 nm scale p–n heterojunction nanochannel was fabricated with ultrasmall grained WO3/CuO nanopatterns in a large area (centimeter scale) through unique one-step top-down lithographic approaches. The fabricated p–n heterostructure nanochannel showed ultrathinness (20 nm thickness) and high aspect ratio (>10) and consisted of highly dispersed p-type dopants and n-type channel materials. This facile heterojunction nanostructure could induce a high degree of extended depletion layer and efficient c...