In situ TEM modification of individual silicon nanowires and their charge transport mechanisms

Correlating the structure and composition of nanowires grown by the vapour-liquid-solid (VLS) mechanism with their electrical properties is essential for designing nanowire devices.In situtransmission electron microscopy (TEM) that can image while simultaneously measuring the current-voltage (I-V) characteristics of individual isolated nanowires is a unique tool for linking changes in structure with electronic transport. Here we grow and electrically connect silicon nanowires inside a TEM to performin situelectrical measurements on individual nanowires at both ambient and high temperature and upon surface oxidation. As-grown, the oxide-free nanowires have nonlinearI-Vcharacteristics. We analyse theI-Vmeasurements in terms of both bulk and injection limited transport models, finding Joule heating effects, bulk-limiting effects for thin nanowires and an injection limiting effect for thick wires when high voltages are applied. When the nanowire surface is modified byin situoxidation, drastic changes occur in electronic properties. We investigate the relation between the observed geometry, changes in the surface and changes in electronic transport, obtaining information for individual nanowires that is inaccessible to other measuring techniques.