Optoelectronic properties of three-dimensional ZnO hybrid structure

Abstract

Three-dimensional (3D) ZnO hybrid structure was fabricated by growing a ZnO buffer layer, a ZnO nanowire array, and a ZnO film continuously through the control of supersaturation conditions. Lower and upper ends of vertically aligned nanowires in this hybrid structure formed seamless interfacial contacts with the buffer layer and the film for current conduction. Photocurrent was generated only when the ultraviolet (UV) light (λ=350nm) was irradiated. This structure also exhibited different atmosphere-dependent responses to the UV light. The optoelectronic properties of the 3D structure are attributed to the photogenerated carriers and the surface reaction of negatively charged oxygen species in ZnO nanowires.

On the formation of well-aligned ZnO nanowall networks by catalyst-free thermal evaporation method

“…It is natural to imagine that this oxidation process reduced the Zn vapor concentration in the growth chamber. In fact, some authors [24,25] have reported the transition from film growth to nanowire growth by altering the Zn vapor supersaturation level. Fig.…”

“…High supersaturation level usually results in a lateral growth mode [24][25][26], and hence the formation of a thick ZnO film was favored at this stage. The pre-coated template layer provides nucleation sites and guides the growth directions of the crystallites.…”

“…With the hillock growth and coalescence, the hillocks were prolonged in shape and necks between them appeared. (3) Due to the continually decrease of Zn vapor concentration, further coarsening of these hillocks was not possible at a certain time, and only 1-D vertical growth was favorable [24][25][26]. Occurrence of 1-D protuberances in Fig.…”

Homoepitaxial ZnO film growth on vertically aligned ZnO nanorods

“…Single ZnO nanowires have been widely investigated for their potential applications to atomic force microscopy (AFM) cantilevers [15], gas sensors [16,17], nanotransistors [18], and logic gate devices [19]. The heterostructures of n-ZnO nanorods on p-GaN for LED applications [20][21][22][23][24] and high power operating nanodevices [25] have also been studied. However, for industrial applications of nanostructures, several tens-thousands of the nanostructures should be used for a single device because practical devices require reproducibility, stability and durability.…”

Ultrasound-assisted synthesis of metal–organic framework nanorods of Zn-HKUST-1 and their templating effects for facile fabrication of zinc oxide nanorods via solid-state transformation

“…Zinc oxide nanomaterials have attracted a considerable attention in the past few decades due to their potential applications in optics [15], optoelectronics [16], photoelectric devices [17], solar cells [18], catalysis [19] and sensors [20]. ZnO is a well-known semiconductor material with a wide band gap of 3.37 eV [21] and large excitonic binding energy of 60 meV [22].…”