Logic gates and computation from assembled nanowire building blocks

Miniaturization in electronics through improvements in established "top-dow n" fabrication techniques is approaching the point where fundamental issues are expected to limit the dramatic increases in computing seen over the pa st several decades. Here we report a "bottom-up" approach in which function al device elements and element arrays have been assembled from solution thr ough the use of electronically welt-defined semiconductor nanowire building blocks. We show that crossed nanowire p-n junctions and junction arrays ca n be assembled in over 95% yield with controllable electrical characteristi cs, and in addition, that these junctions can be used to create integrated nanoscale field-effect transistor arrays with nanowires as both the conduct ing channel and gate electrode. Nanowire junction arrays have been configur ed as key OR, AND, and NOR logic-gate structures with substantial gain and have been used to implement basic computation.