Scanning Photocurrent Microscopy of as-Grown Silicon Nanowire Metallurgical Junctions

Abstract

ABSTRACTDuring the epitaxial bottom up growth of nanowire (NW) arrays, occasional kinks in growth direction can lead to intersecting and consequently self-welded crystalline connections between NWs. In order to study these self-welded metallurgical NW junctions, a NW bridge device architecture which requires no post-growth processing was used to grow and stabilize Si NW junctions. Scanning Photocurrent Microscopy (SPCM) was used to study the optoelectronic properties of the NW junctions as well as the characteristics of the NW bridge devices. SPCM measurements show a bias dependent photocurrent (PC) response at the NW junction indicating local band bending at this location. A decay of the PC response away from the junction is also seen in the secondary NW channel ensuring an electrical connection. These junction properties may be important for ensemble NW optical devices.