Incorporation of cadmium sulfide into nanoporous silicon by sequential chemical deposition from solution

The incorporation of cadmium sulfide into porous silicon is investigated with the aim of realizing electrical contacts with the inner surface of the porous material. This is achieved by using a sequential chemical bath deposition method, consisting of the deposition of a few monolayers of cadmium hydroxide in a first solution, and conversion into cadmium sulfide in a second solution containing thioacetamide. This sequence is repeated five times until the pores are completely full. The chemical deposition process is assessed by a detailed analysis of the solution chemistry. Characterizations of the deposit by scanning electron microscopy, X-ray fluorescence, Auger electron spectroscopy, Rutherford back scattering, and X-ray photoelectron spectroscopy are presented and-confirm good pore penetration by CdS, with only a weak concentration gradient from the top to the bottom of the porous layer.