Growth of α-Fe films on n-Si(111) substrate by pulsed electrodeposition in a non-aqueous solution

Fe thin films were grown directly on n-Si(111) substrates without any buffer layer by pulsed electrodeposition in a 0.1 M FeCl2+methanol electrolyte solution. Over the potential ranges from 1.0 V to 1.4 V, the formation of Fe nuclei in the early deposition stages proceeds through a three dimensional (3D) of instantaneous nucleation mode rather than a progressive one. According to this nucleation mode, the estimated nucleus density (N0) and the diffusion coefficient (D) are of orders of ∼1010 cm−2 and ∼10−9 cm2 s−1, respectively. From the as-deposited sample obtained using the potential pulse of 1.4 V and 300 Hz, it is found that Fe nuclei grows to 3D islands with the average size of about 100 nm in early deposition stages. For a longer deposition time, the sizes of Fe nuclei increases progressively and by a coalescence of the nuclei a continuous Fe films grows on the Si surface. In this case, the Fe films show a highly oriented columnar structure and X-ray diffraction (XRD) pattern reveal that the phase α-Fe grows on the n-Si(111) substrates.