Electron-irradiation-induced phase separation in GaSb nanoparticles

Electron irradiation effects in GaSb compound nanoparticles have been studied by transmission electron microscopy, in order to examine structural stability under electron irradiation in a nanometer-sized system. It is revealed that when 75 keV electron irradiation was carried out in approximately (10-25)-nm-sized GaSb particles kept at 423 K, a phase separation of the GaSb compound was induced to form a two-phase structure consisting of a crystalline antimony core and a liquid gallium shell. The phase separation was induced neither by 75 keV electron irradiation in GaSb nanoparticles kept at more than 443 K or less than 363 K nor by 200 keV electron irradiation in particles kept from 363 to 443 K. It is suggested that the phase separation in GaSb nanoparticles may be induced by electronic excitations rather than knock-on displacements.