Germanium growth in low dimensions based on relaxed-porous silicon by using a simple way of electrochemical deposition

Abstract

Porous silicon (PS) technology was used to grow Ge micro-flower on the surface of Si substrates with rough morphology. Low dimensions nanorods were also fabricated directly on the Si substrates through Ge deposition using a simple and low-cost of electrodeposition method for comparison. The characteristics of low dimensions nanorods were investigated for both substrates PS and Si using scanning electron microscopy (SEM), EDX, grazing-angle X-ray diffraction (XRD), and Raman spectra measurements of nanostructures grown on both PS and Si substrate. The texture obtained from SEM images showed thatthe nanorods were covered by micro-flowers and highly oriented on the porous silicon substrate. Furthermore, the length of nanorods on porous silicon decreased from 10μm to 200 nm and the diameter from 500-200 nm to100 nm. Ge lattice parameters and crystallite size grown on PS and Si were calculated from X-ray diffractograms. It was found that the Ge structures for PS and Si were polycrystalline with a cubic system, whilst the elastic strain on PS was lower than Si substrate. This indicates that Ge on porous lattice is more relax than on silicon. The Raman spectra showed that Ge structure shifted slightly towards to the upper frequency compared with bulk Ge.