Atomic Force Microscopy (AFM) Studies of 2D Cu₂S, Cu₉S₅, Ag₂S and Ni₅P₄ Monolayers

2D layered materials have raised a lot of interest due to their great potential for nano-scale electromechanical systems and electronic device applications. Mono and few-layered materials exhibit a wide range of unique electrical, optical, mechanical and thermal properties, which do not exist in their bulk structure. In this study, we successfully synthesized layered bulk copper sulfides, silver sulfide and nickel phosphate by thermal annealing under an inert gas (Ar) using chemical vapor deposition (CVD). We successfully separated them to 1.5 nm monolayer and a few-layers flakes by sonicating the bulk materials in ethanol. The morphology and thickness of the flakes on a Si/ SiO₂ substrates were measured using AFM technique. The electrical conductivity of the obtained flakes was tested by peak force tunneling atomic force microscopy (PF-TUNA) and we can demonstrate the correlation between conductivity and the number of layers. Moreover, we observed the heigher conductivity for Ni₅P₄ flakes.