Cross-sectional SEM image of Si cores with a spacing of 1.5 μm, buried in nanoPSi. For a 250-keV proton beam, different line fluences were used: 5 × 1010/cm, 8 × 1010/cm, and 1 × 1011/cm in 0.02 Ω cm p-type Si. Subsequent electrochemical etching was carried out using several current densities: (a) 300 mA/cm2, (b) 30 mA/cm2, and (c) 3 mA/cm2.
Recio-Sánchez et al. Nanoscale Research Letters 2012 7:449 doi:10.1186/1556-276X-7-449