Zinc oxide (ZnO) nanorods are grown hierarchically on cuprous oxide (Cu 2 O) nanoneedles to form a Cu 2 O/ZnO hetero-nanobrush assembly. This increases the overall aspect ratio, which helps to enhance the field emission properties of the system. Also, the charge separation and transport are facilitated because of the multiple p-n junctions formed at p-Cu 2 O/n-ZnO interfaces and quasi-1-D structures of both the materials, respectively. This helps to significantly enhance the photocatalytic properties. As compared to only Cu 2 O nanoneedles, the Cu 2 O/ZnO hetero-nanobrush shows excellent improvement in both field emission and photocatalytic applications.

Cu(2)O nanoneedles are synthesized on a copper substrate by a simple anodization and reducing ambient annealing protocol. ZnO nanorods are grown on ITO coated glass by a low temperature chemical route. The electronic and photo-response properties of the p-Cu(2)O/n-ZnO flip-chip heterojunction are then studied and analyzed. We show that the I-V characteristic is rectifying and the junction exhibits a good photoresponse (∼120% under 1 V reverse bias) under AM 1.5 (1 Sun) illumination. This nano-heterojunction photo-response is far stronger as compared to that of a pulsed laser deposited thin film p-Cu(2)O/n-ZnO heterojunction, which can be attributed to higher junction area in the former case.

Strong enhancing effect of plasmonic Au nanoparticles on the photoelectrochemical performance of a ZnFe2O4/ZnO heterojunction used as photoanode for water splitting application is demonstrated. The material properties of Au/ZnFe2O4/ZnO complement each other remarkably well in the configuration proposed in terms of their optical, electronic, and catalytic properties.

A heterostructure formed by a layer of agarose gel drop-cast on a hydrothermally grown layer of ZnO nanorods on fluorine-doped tin oxide (FTO)-coated glass is examined for photoresponse with a top platinum tip contact. This ionic-gel-based hybrid device shows three orders of magnitude higher photocurrent as compared to the case of bare ZnO nanorods film.