Fabrication of composite based on GeSi with Ag nanoparticles using ion implantation

Comparative analysis of the structural and optical properties of composite layers fabricated with the aid of implantation of single-crystalline silicon ($c$-Si) using Ge$^+$ (40 keV/1 $\times$ 10$^{17}$ ions/cm$^2$) and Ag$^+$ (30 keV/1.5 $\times$ 10$^{17}$ ions/cm$^2$) ions and sequential irradiation using Ge$^+$ and Ag$^+$ ions is presented. The implantation of the Ge$^+$ ions leads to the formation of Ge: Si fine-grain amorphous surface layer with a thickness of 60 nm and a grain size of 20–40 nm. The implantation of $c$-Si using Ag$^+$ ions results in the formation of submicron porous amorphous $a$-Si structure with a thickness of about 50 nm containing ion-synthesized Ag nanoparticles. The penetration of the Ag$^+$ ions in the Ge: Si layer stimulates the formation of pores with Ag nanoparticles with more uniform size distribution. The reflection spectra of the implanted Ag: Si and Ag: GeSi layers exhibit a sharp decrease in the intensity in the UV (220–420 nm) spectral interval relative to the intensity of $c$-Si by more than 50% owing to the amorphization and structuring of surface. The formation of Ag nanoparticles in the implanted layers gives rise to a selective band of the plasmon resonance at a wavelength of about 820 nm in the optical spectra. Technological methods for fabrication of a composite based on GeSi with Ag nanoparticles are demonstrated in practice.