Synthesis and characterization of ZnO nanostructures and ZnO/Ni1-xCuxO heterostructures Application to photovoltaics

In the present work, we prepared heterojunctions in the form of thin films based on ZnO and NiO, these thin films were deposited by pyrolysis spray technique on glass substrates. The adopted technique is simple, not expensive, it allows for deposition with a controllable property depending on the conditions of preparation. The first objective of this work is the preparation of thin films of ZnO; our interest is on the optimization of the parameters influence as a (molarity and substrate temperature on the physical and optical properties of ZnO thin films. On the other object is the preparation of thin films of NiO and the study of the doping level influence and substrate temperature on the structural, optical and electrical properties. One has used copper as source of dopants; the doping level was varied from 0 to 4% by weight. The structural study of films by XRD showed that all ZnO films obtained are polycrystalline with a hexagonal wurtzite structure and a preferred orientation along the direction (002) and for NiO films, the structure is cubic with a preferred orientation along the direction (111). While the transmission spectra show that this film exhibited a transmission was detected between 45 and 65% in the visible region. Whereas the electrical characterization I(V) was used to determine the electrical parameters of the realized Na and Al codoped NiO thin films, which revealed that the minimum values of Sheet Resistance was registered for Na (2%) and Al (1%). When studying the effect of the deposition temperature of nickel oxide and its doping ratio with copper on the ZnO/Ni1-xCuxO heterojunctions, we observed a significant improvement in the crystallization of zinc oxide, along with the growth and stability of nickel oxide. These changes led to a significant enhancement in the transparency of the junctions, thereby enhancing their optical properties