Interface-controlled Ag₂O-Si wafer heterojunctions showing current rectification and light-responsive conductivity

To investigate the presence of current rectification behavior in facet-controlled Ag₂O/Si heterostructures, Ag₂O cubes, octahedra, and rhombic dodecahedra exposing respective {100}, {111}, and {110} surfaces were synthesized. Their I-V curves were collected using a conductive atomic force microscope (AFM). While all the Ag₂O polyhedra exhibited high conductivity responses, octahedra were particularly conductive. Conductivity measurements were also performed on Si {100}, {111}, and {110} wafers, showing Si {111} wafer to be the most conductive. Subsequently, these Ag₂O polyhedra were added to different silicon wafers for electrical conductivity measurements by making electrical connections to the heterostructures. The Ag₂O octahedron/Si {100} wafer and rhombic dodecahedron/Si {110} wafer cases exhibited the best and clean current-rectifying behavior. Under white light-emitting diode (LED) illumination, the Ag₂O octahedron/Si {100} wafer, cube/Si {111} wafer, and rhombic dodecahedron/Si {111} wafer combinations showed significant photocurrent enhancement for photodetector applications. Thus, by controlling the contacting crystal faces in semiconductor heterojunctions, it is possible to utilize the semiconductor facet effects to fabricate novel transistors, especially if the top semiconductor can be produced by a solution approach for incorporating into the chip manufacturing process.