Growth of atomic-scale aluminum film on GaAs substrate

We present the method for large-area growth of single-crystalline Al films in atomic scale on GaAs substrate by using molecular beam epitaxy. The grown Al film of thickness down to 5 nm exhibits smooth surface morphology, a clear and single X-ray diffraction peak in θ-2θ scan, and nearly transparent optical response. This work open a window for ex-situ studying quantum size effect in metal film.