A study of nano materials and their reactions in liquid using in situ wet cell TEM technology

Several nano material and reaction systems were in situ monitored with an electrochemical TEM wet cell set up. In a 1 g/L sliver particle aqueous solution, the particles were observed to be ca. 10 nm sized, in both discrete particle and nano cluster forms. The silver particles were attached to the 50 nm-thick Si₃N₄ windows of the wet cell and could not move freely in the liquid. With a SiCl₄ liquid loaded in the wet cell, silicon nano materials were controllably grown on the wet cell windows by means of a liquid phase electron beam induced deposition (EBID) method. The deposited nano dots were nicely round-shaped, and demonstrated a power law growth dependency on beam exposure time in a log-log plot. In a NiCl2 solution/Ni system, both electrochemical deposition and dissolution of the nickel nano films were observed while applying electric biases on to the nickel electrodes in the wet cell. Instead of extensional growth on existing crystals, interestingly, it is more commonly observed that new nickel nano particles grow out in front of the existing film first and then merged into the film. The wet cell set up is demonstrated to be a versatile tool for nano liquid system research.