Ion bombardment of gallium thin films

In this letter we describe bombardment and annealing experiments carried out independently on gallium. Systems such as gallium which show metastable phase formation during static or dynamic undercooling might also be expected to form metastable phases during ion bombardment. Bombardment experiments were carried out using gallium or argon ions produced on a 100 kV heavy-ion accelerator. Gallium samples were evaporated in situ from alumina boats onto sapphire (for electrical measurements) and thin-film carbon (for electron diffraction) substrates during the same evaporation. After deposition, both samples were bombarded in turn at 13 K with the same ion dose. Electron diffraction, 4-probe a.c., and 2-probe d.c. electrical measurements were used to monitor the effects of bombardment and annealing. Experimental details are given. Results are given and discussed. (author)