a Department of chemistry, College of science, King Saud University, P.O. Box

2455, Riyadh 11451, Saudi Arabia

b Department of Mechanical Engineering, Inha University, Incheon,South Korea c Department of Physics, Paavendhar College of Arts & Science, Salem - 636121, India

Employing a green synthesis technique, we produce cost-effective zinc oxide nanoparticles and calcium-doped zinc oxide nanoparticles by utilizing Citrus sinensis fruit extract as an efficient reducer and encapsulating agent. XRD analysis confirmed a wurtzite structure for the as synthesized ZnO and calcium doped ZnO nanoparticles. Oxidation states and quantification of the element on the surfaces of pure and Ca-ZnO was achieved through XPS investigations. Nano-flakes structures of the synthesized samples are prominently depicted in the HR-SEM image, providing visual insight into their morphology. The elemental analysis and their quantity were discerned using EDX spectrum. Moreover, Magnetization– Field (M–H) hysteresis curves demonstrated diamagnetic behavior at room temperature.