Transmission electron microscopy study on iron silicide nanoparticles synthesized by electron beam evaporation technique

摘要

Beta iron disilicide (beta-FeSi_2) possesses a direct band gap of 0.8-0.85 eV, so it is anticipated as a candidate material for a component of Si-based optoelectronic devices. To control the physical properties of beta-FeSi_2, it is of technological importance for understanding its formation process. In this study, we synthesized completely separated iron silicide nanoparticles on a Si(100) substrates using an electron-beam evaporation technique and characterized them by transmission electron microscopy (TEM) [1]. Chemically etched Si(100) substrates were baked in a deposition chamber at temperature of 923K for lhr to clean the surface. Then Fe thin film with a thickness of 2-10 nm was deposited on the substrate. An amorphous Al_2O_3 film was further deposited to protect the Fe thin film from oxidation. The as-deposited specimens were annealed to form beta-FeSi_2 nanoparticle. Microstructures as well as their structural evolution were on thermal annealing examined by ex-situ and in-situ TEM using a JEOL JEM-3000F.