Heteroepitaxial Self Assembling Noble Metal Nanoparticles in Monocrystalline Silicon

Abstract

Embedding metal nanoparticles in crystalline silicon possesses numerous possible applications to fabricate optoelectronic switches, increase efficiency of radiation detectors, decrease the thickness of monocrystalline silicon solar panels and investigate fundamental properties. Noble metal nanoparticles made of gold or silver are grown in cavities in monocrystalline silicon formed by helium ion implantation and high temperature annealing at depth greater than 500 nm from the surface. Metals are introduced into the system by low energy ion implantation or physical vapor deposited thin film on the surface, and diffused into cavities by heat treatment. Nanoparticles nucleate on the inner surface of cavities heteroepitaxially and form face centered cubic crystal structure in the case of silver. Excessive heat treatment causes metal to be emitted from nanoparticles into bulk after trapping and nanoparticle formation. Helium ion implantation, annealing and diffusion heat treatment conditions have been optimized so that residual crystalline damage, point defects and dislocations, is reduced in monocrystalline silicon substrate.