Abstract:
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.