Intact sublimation of silicon nanocrystals evidenced via HREM imaging and EELS in a dedicated STEM

U Bangert, M Gass, L Siller, P R Coxon, Y Chao, B R Horrocks
2008 Journal of Physics, Conference Series  
Silicon nano crystals (NCs) have attracted considerable interest for possible uses in optoelectronics 1 As the particle size decreases the properties of NCs become increasingly sensitive to the surface termination. 2,3 Monolayer chemistries 4-10 have been exploited to control the physicochemical properties. NCs are often prepared by vapour-phase deposition techniques; using these they can be conveniently analysed via gas phase analysis techniques, such as mass spectrometry. This cannot be
more » ... ed, however, if NCs are not synthesized in the gas phase. Here we present a STEM study of undecyl-capped SiNCs, evaporated intact upon heating in ultrahigh vacuum at 200 o C and collected on a variety of solid substrates, including carbon-coated TEM grids. The BF-and HAADF lattice images confirm that the particles have a crystalline core with Si-lattice spacings. The presence of Si in the core is also confirmed by Si-L edge EELS, which reveals furthermore the presence of a surface oxide.
doi:10.1088/1742-6596/126/1/012066 fatcat:7xdb3hd7tfdtviog4twfou6jha