LAUSR

We report here structural, electrical, photoluminescence (PL), and optical investigations of ZnO nanoparticles. The ZnO samples are initially sintered at various temperatures (Ts) (600–1200 °C) temperatures and their size is reduced twice to nanoscale by using ball friction at 200 rpm rotational speed and 30 min duration. It is found that the Ts do not influence the well-known peaks associated with the ZnO hexagonal structure, whereas the constants of the lattice and the average crystallite diameters are affected. Although the nonlinear area is observed for all samples in the I-V curves, the breakdown field EB and nonlinear coefficient β are moved to lower values as Ts increases, while the residual voltage Kr and nonlinear conductivity (σ2) are increased. The empirical relations for Kr, EB, and β as a function of Ts are; Kr = 0.004 Ts − 0.487, EB = − 1.786 Ts + 2559.5 and β = − 0.052 Ts + 75.19. On the other hand, a maximum UV absorption shift (Amax) is obtained at 412 nm, 400 nm, 384 nm, and 326 nm as the Ts increases up to 1200 °C. For each sample, two different energy band gap values are obtained; the first is called the basic bandgap (Egh) and its value above 3 eV, while the second is called the optical band gap (EgL), and its value below 2.1 eV. Moreover, the empirical relations of them are Egh = 0.002 Ts − 0.24, Egl = − 0.0033 Ts + 5.242 and ∆E =− 0.0015 Ts + 5.002. Furthermore, the values of (N/m*) and lattice dielectric constant eL are increased by increasing Ts up to 1200 °C, while the vice is versa for the interatomic distance R. The dielectric loss tan δ is almost linear above 4 eV for all samples, and it decreases sharply as the Ts increases. The optical and electrical conductivities σopt and σele are decreased as the Ts increases up to 1200 °C. Finally, the characteristic of UV band edges against the optimum value of PL intensity for the samples shows 8-continuous peaks. Furthermore, the PL intensity of the peaks is decreased by increasing Ts and also by shifting the UV wave number towards the IR region.