Sample Preparation for Electron Microscopy Sectioning

SEM requires almost no sample preparation beyond fabrication of the microparticles because pSi is a semiconductor formed in solutions of HF and therefore 

SEM beam is in the low micron range [61], and so does not allow for sufficient z-resolution to differentiate thin samples from their substrates, thus precluding an accurate analysis of the sample composition. Therefore, the use of TEM and STEM, where the electron beam travels solely across the specimen, provides a more accurate characterization of the chemical composition of the sample. The 2 A spot size rastering beam of STEM also allows for minimum background noise and high-resolution x,y mapping of the sample surface. 

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