Structural and Electrical Characteristics of Sol-Gel ZnO Films on Black Silicon

In this work, zinc oxide (ZnO) films were deposited on silicon (Si) substrates with and without Black Silicon (BS) using the sol-gel spin-coating method. The nanotexturing of the Si surface was performed via reactive ion etching, resulting in the formation of a conical nanoneedle array that enhanced light trapping efficiency. X-ray Diffraction (XRD) analysis confirmed that the ZnO films exhibited a polycrystalline hexagonal wurtzite structure. The formation of n-ZnO/p-Si heterostructures was validated through Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and current-voltage (I–V) measurements. The incorporation of BS at the heterostructure interface significantly enhances the spectral response across the entire wavelength range due to superior light-trapping properties and an increased contact area at the heterojunction. These findings are highly relevant for the development of photodetectors and other optoelectronic devices based on ZnO and BS.