Use of Phosphine as an n-Type Dopant Source for Vapor-Liquid-Solid Growth of Silicon Nanowires

摘要

Phosphine(PH_3)was investigated as an n-type dopant source for Au-catalyzed vapor-liquid-solid(VLS)growth of phosphorus-doped silicon nanowires(SiNWs).Transmission electron microscopy characterization revealed that the as-grown SiNWs were predominately single crystal even at high phosphorus concentrations.Four-point resistance and gate-dependent conductance measurements confirmed that electrically active phosphorus was incorporated into the SiNWs during VLS growth.A transition was observed from p-type conduction for nominally undoped SiNWs to n-type conduction upon the introduction of PH_3 to the inlet gas.The resistivity of the ntype SiNWs decreased by approximately 3 orders of magnitude as the inlet PH_3 to silane(SiH_4)gas ratio was increased from 2 x 10~(-5)to 2 x 10~(-3).These results demonstrate that PH_3 can be used to produce n-type SiNWs with properties that are suitable for electronic and optoelectronic device applications.