Change in the surface state of the single-crystal germanium as a result of implantation with silver ions and annealing with light pulses

Single-crystal $c$-Ge plates implanted with Ag$^+$ ions with an energy of $E$ = 30 keV, current density of the ion beam $J$ = 5 $\mu$A/cm$^2$ and a dose of $D$ = 2.5· 10$^{16}$ ion/cm$^2$ were subjected to rapid thermal annealing by single light pulses of various durations from 1 up to 9.5 s. By scanning electron microscopy and optical reflection spectroscopy measurements it was shown that after ion implantation an amorphous porous Ag : PGe layer of spongy structure, consisting of Ge nanowires, is formed on the surface of $c$-Ge substrates. It was found that the annealing with an increase in the pulse duration up to 5 s successively leads to an increase in the Ge nanowire diameters from 26 to 35 nm. With longer pulses, the porous Ag : PGe structure is destroyed and Ag evaporates from the implanted layers.