We present a review on the formation of gold silicide nanostructures using in situ temperature dependent transmission electron microscopy (TEM) measurements. Thin Au films of two thicknesses (2.0 nm and 5.0 nm) were deposited on Si (1 1 0) substrate under ultra-high vacuum (UHV) conditions in a molecular beamepitaxy (MBE) system. Also a 2.0 nm thick Au film was deposited under high vacuum condition (with the native oxide at the interface of Au and Si) using thermal evaporation. In situ TEM measurements (for planar samples) were made at various temperatures (from room temperature, RT to 950 degrees C). We show that, in the presence of native oxide (UHV-MBE) at the interface, high aspect ratio (approximate to 15.0) aligned gold silicide nanorods were observed. For the films that were grown with UHV conditions, a small aspect ratio (similar to 1.38) nanogold silicide was observed. For 5.0 nmthick gold thin film, thicker and lesser aspect ratio silicides were observed. Selected area diffraction pattern taken at RT after the sample for the case of 5.0 nm Au on Si (1 1 0)-MBE was annealed at 475 degrees C show the signature of gold silicide formation. (C) 2009 Elsevier B.V. All rights reserved.