Gold Contamination in VLS-Grown Si Nanowires: Multiwavelength Anomalous Diffraction Investigations

Silicon nanowires were grown by gold-catalyzed chemical vapor deposition in the vapor liquid solid mode. In this paper, we use grazing incidence X-ray diffraction and multiwavelength anomalous diffraction to investigate the presence of gold and its effects on silicon nanowire strain after different chemical and physical treatments. We especially focus on the efficiency of the thermal oxidation-oxide etching cycle to remove the gold contamination. Analysis reveals a decrease of the contamination and a core-shell like spatial distribution of gold, but also shows that this technique is not efficient enough to remove all traces of gold from the nanowires.