Influence of Mass Transport on Formation of Si-Nanostructures

Abstract

Nanowire-like, condyloid-like and flakes of Si-nanostructures weresynthesized by thermal evaporation under different mass transportconditions by changing the ambient pressure. The structural analysisshows that a higher mass transport rate isnot favourite for the formation of fine single crystalline nanowireswhen the substrate placed closely to the thermal vapour source. Thehigher mass transport rate can induce a lower Si partial pressure nearthe source and hence results in a lower supersaturation near thesubstrate. Experimental results reveal that the formation ofSi-nanowires is not controlled by mass transport but by surfaceprocess. The driving force on the surface is the key factor for theformation of well-crystallized nanowires.