Atmospheric pressure induced atomic diffusion into solid crystal

Abstract

Gaussian-shape diffused nanolayer, formed due to atomic diffusion of gold into silicon crystal, shows wave-front-like movement with time when the system is in ambient condition, while it remains almost static as long as it is in ultrahigh vacuum condition. This is clear evidence of simple atmospheric pressure induced diffusion of atomic gold into the silicon crystal and provides an interesting concept of inherent pressure inside a crystal structure. The atmospheric pressure at the surface and its gradual decreasing nature from the surface to inside crystal acts as driving and retarding forces, respectively, which can be used to control the formation and movement of the diffused layer in nanolevel. Such diffusion also depends on the crystal structure and freeness of the diffusing atoms. The latter increases as the thickness and/or coverage of the gold layer decreases.