Effect of the doping concentration on the properties of silicon nanowires

Silicon nanowires (SiNWs) become interesting nanostructures for several applications such as electronic, photovoltaic, and maybe in a short future as nanopower source for nanorobotics. There are several experimental methods to form SiNWs. In this study, we use the etching assisted silver method in a HF solution. We investigate the effect of the doping concentration (P and P+ silicon) on the morphological, optical and electronic properties of silicon nanowires prepared at different etching times. We found that the morphological, optical and electronic properties of the formed films depend on the doping level of the used silicon substrate. The total reflectivity of some films reaches 1%. However, a decrease of the measured effective lifetime as a function of the etching time is obtained. Using the light-beam-induced-current (LBIC) profiles measured on a MIS structure fabricated on P and P+-SiNWs, we found that the effective diffusion length is in the range of 100 μm for P+-SiNWs, however it is only in the range of 60 μm for P-SiNWs. This was attributed to the reflectivity and homogeneity of the formed films.