Impact of seed layer annealing on the optoelectronic properties of double-step CBD grown n-ZnO nanowires/p-Si heterojunctions

Abstract In the current work, n-ZnO nanowires are grown by employing double-step chemical bath deposition (CBD) technique on p-Si substrate for the fabrication of n-ZnO nanowires/p-Si heterojunction diodes. The as-deposited ZnO seed layer is furnace annealed at 400 °C and 600 °C for 30 min in argon ambient for studying comparative changes of their optoelectronic properties. The systematic change of surface morphology, chemical compositions, crystallite structure, oxidation states, defect levels and photodetecting properties due to annealing of the seed layer has been investigated. Annealing the seed layer at 400 °C exhibits a nanosphere-like structure and provides superior nucleation sites for vertical growth of the nanowires in comparison to the as-deposited and 600 °C -annealed samples. The electrical, electro-optical and physical characterization results suggest the nanowires grown on 400 °C -annealed ZnO seeds to provide superior performance.