In situ observation of dynamic processes in space and time is essential for understanding fundamental phenomena with underlying mechanisms [1-5]. 4D electron microscopy is able to image dynamics in both space and time with the highest temporal resolution down to femtosecond. In this talk, I will present our recent results on the phase reaction dynamics in Au-GaAs materials [1] using single-pulse mode of 4D electron microscopy [Fig. 1]. Because of the irreversible nature of involved processes, the reactions were initiated with a single excitation pulse, whereas a single electron pulse was used to image the structural evolution on the nanosecond time scale. The transient structural changes were recorded in three time domains: before, during and after the process ended. Useful thermodynamic parameters of the newly formed phases were obtained. The mechanisms that account for the observed phase reaction dynamics of Au-GaAs nanostructures will be discussed. Our work provides an efficient way of quantitatively determining physical/chemical properties of a nanoscale object with a tiny small quantity, especially when not available in bulk counterparts.<br/><br/>

Ultrafast imaging of phase reaction dynamics in Au-GaAs nanowires using 4D electron microscopy

256th National Meeting (2018)

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