SEM image and EDS map of a 29-μm-thick sample. SEM image (a) and corresponding EDS chemical map (b) for Er (blue) and Si (red) of an Er-doped 29-μm-thick PSi sample. In both cases, two arrows (one on each side of the image) indicate the interface between PSi and crystalline Si, and a green line indicates the surface of the sample. The nominal amount of Er inserted within the pores is 2%. The PSi layer in the micrograph is on the top half of the image (a) (lighter gray), and the bulk crystalline Si is on the bottom half (darker gray). The EDS analysis (b) confirms that Er atoms are present in the whole PSi layer thickness.
Mula et al. Nanoscale Research Letters 2012 7:376 doi:10.1186/1556-276X-7-376