Tunnel junctions in a III–V nanowire by surface engineering

We demonstrate a simple way of fabricating high performance tunnel devices from p-doped InAs nanowires by tailoring the n-doped surface accumulation layer inherent to InAs surfaces. By using appropriate ammonium sulfide based surface passivation before metallization without any further thermal treatment, we demonstrate characteristics of tunnel p-n junctions, namely Esaki and backward diodes, with figures of merit better than previously published for InAs homojunctions. The further optimization of both the surface doping, in a quantitative way, and the device geometry allows us to demonstrate that these nanowire-based technologically-simple diodes have promising direct current characteristics for integrated high frequency detection or generation.