# Formation of ZnO/CuO Heterostructures Based on Quasi-One-Dimensional Nanomaterials
## 6 Conclusions  
The application of nanostructured metal oxides enables increased functionality and decreased power consumption of sensor devices and microsystems, micro- and optoelectronic systems under development while reducing the mass and size of components. For this reason, such materials are of great interest, for studies as well as for a wide range of applications, and are being actively researched and developed. Much attention has been paid to the application of synthesized quasi-one-dimensional metal oxide nanostructures, including copper and zinc oxides. The main obstacle to the wide practical application of existing physical and chemical methods for the synthesis of quasi-one-dimensional oxides is that the morphology of the deposited nanostructures depends on the thickness of the seed layer and the properties of the substrate used. Growth mechanisms are influenced by many factors, so even small changes in synthesis conditions may lead to significant modifications in the morphology and properties of the created nanomaterials. Therefore, the development of reliable methods for producing nanomaterials and heterostructures remains a topical issue. Copper oxide nanowires have become important in optoelectronic devices and energy conversion systems. Techniques for growing copper oxide nanowires include wet-chemical, solution-based, electrochemical and hydrothermal. Thermal and plasma oxidation methods are also used. Despite the fact that the desired improved properties have been achieved, materials containing copper oxide nanowires cannot yet be produced in large quantities, for wider use. It is, therefore, necessary to continue searching for the most efficient synthesis processes that provide not only high quality and improved properties of such materials but also higher productivity. Possible implementations of the quasi-one-dimensional structures include metal-oxide layered materials that can be used as materials for electrical contacts. The performance properties of such materials tend to improve with an increase in the dispersion and uniformity of the oxide phase distribution on the metal surface. However, the morphology of the arrays of quasi-one-dimensional materials that are synthesised on the substrate, including ZnO nanowires, is extremely sensitive to the synthesis conditions and is difficult to control, and only a few studies are devoted to this specific topic. Therefore, the consideration of this issue is still relevant. By creating heterojunctions with other metal oxides, the properties of zinc oxide-based materials can be improved. Copper oxide (CuO), which is an indirect-gap semiconductor with p-type conductivity, can be used for heterojunction formation. Bulk heterojunctions in ZnO/CuO-based devices can be formed using one-dimensional ZnO nano-objects, and no ordering of arrays of such nano-objects is required. The formation of a p-type conductivity layer is achieved by the deposition of copper oxide, which fills the space between the one-dimensional zinc oxide objects, creating contact with the current-carrying electrode. The use of synergistic effects of heating and laser-induced vibrations has allowed the creation of a new approach for the formation of quasi-dimensional nanostructured metal oxides by laser-matter interaction. The condition that allows intensified mass transfer has been identified as the non-stationary stress-strain state caused by laser-induced vibrations. The knowledge of this synergetic effect--a newly identified physical effect allows significant progress in developing a novel approach for the creation of nanostructures and heterostructures of materials. Morphological characteristics are critical for many applications, so controlling these parameters by changing the synthesis conditions is an important task. This task is solved by the adaptation of the laser beam shape and the redistribution of energy and power density by using appropriate optical systems.