Formation of Porous Germanium Layers by Silver-Ion Implantation

Abstract

We propose a method for the formation of porous germanium (P-Ge) layers containing silver nanoparticles by means of high-dose implantation of low-energy Ag⁺ ions into single-crystalline germanium (c-Ge). This is demonstrated by implantation of 30-keV Ag⁺ ions into a polished c-Ge plate to a dose of 1.5 × 10¹⁷ ion/cm² at an ion beam-current density of 5 μA/cm². Examination by high-resolution scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) microanalysis, and reflection high-energy electron diffraction (RHEED) showed that the implantation of silver ions into c-Ge surface led to the formation of a P-Ge layer with spongy structure comprising a network of interwoven nanofibers with an average diameter of ∼10–20 nm Ag nanoparticles on the ends of fibers. It is also established that the formation of pores during Ag⁺ ion implantation is accompanied by effective sputtering of the Ge surface.