Remote p-Doping of InAs Nanowires

We report on remote p-type doping of InAs nanowires by a p-doped InP shell grown epitaxially on the core nanowire. This approach addresses\nthe challenge of obtaining quantitative control of doping levels in nanowires grown by the vapor−liquid−solid (VLS) mechanism. Remote\ndoping of III−V nanowires is demonstrated here with the InAs/InP system. It is especially challenging to make p-type InAs wires because of\nFermi level pinning around 0.1 eV above the conduction band. We demonstrate that shielding with a p-doped InP shell compensates for the\nbuilt-in potential and donates free holes to the InAs core. Moreover, the off-current in field-effect devices can be reduced up to 6 orders of\nmagnitude. The effect of shielding critically depends on the thickness of the InP capping layer and the dopant concentration in the shell.