Realization of a linear germanium nanowire p-n junction.

Germanium nanowires grown by chemical vapor deposition exhibit a peculiar dopant incorporation mechanism. The dopant atoms, such as boron and phosphorus, get incorporated through the wire surface, a mechanism which limits the doping modulation along the wire length, and therefore the fabrication of more elaborate structures that combine both n- and p-type doping. Using a novel device design that circumvents these constraints, we demonstrate here a linear Ge nanowire p-n junction.