Geometric model for metalorganic vapour phase epitaxy of dense nanowire arrays

We propose a geometric model to estimate the contribution of substrate surface diffusion to growth of dense nanowire arrays using metalorganic vapour phase epitaxy. It is shown that the nanowire mantle area becomes the most significant collector of growth material when the nanowire diameter is large and the inter-nanowire pitch is small. It is concluded that this growth regime is important for the array geometries typically used for optoelectronic and photovoltaic applications of nanowires. The growth rate under these conditions is also not constant with time, due to the growing nanowire mantle area. This result was confirmed by experiments in which dense arrays of InAs nanowires were grown and the nanowire growth rate was measured as a function of time.

► A simple geometric model is presented for nanowire growth in dense arrays.
► Nanowire growth within dense arrays is insensitive to the substrate surface.
► The model predicts that the growth rate within dense matrices increases with time.
► Growth experiments of InAs nanowire arrays confirm a non-constant growth rate.