Electrical contact fabrication on vertically aligned ZnO nanowires investigated by current sensing AFM

Abstract

We present a simple method for generating vertically aligned (VA) ZnO nanowire (NW) arrays with tailored electrical top contacts, suitable for photodetector and photovoltaic applications. ZnO NWs were synthesized on Si substrate in house using a hydro-thermal method, producing dense and highly organized vertical ZnO NW ($50-100 nm) arrays. The vertical geometry of the NW arrays facilitated further processing of the NW structures and streamlined in situ characterization of individual NWs as well as entire NW ensembles. The top contact metallization involved depositing a thin film of low work function metals such as aluminum (5 nm) followed by a thin film of gold (15 nm) onto NW arrays, partially embedded in an insulating silsesquioxane-based material (SOG-400F). The I-V characteristics of individual ZnO NWs were measured using current sensing atomic force microscopy (CS-AFM). Compared with arrays of as-grown ZnO NWs, the metalized top contacts of NWs resulted in improved I-V characteristics with good Ohmic behavior at the metal-semiconductor contact (MSC).

Resistive Switching and Polarization Reversal of Hydrothermal-Method-Grown Undoped Zinc Oxide Nanorods by Using Scanning Probe Microscopy Techniques

“…Hence, the Pt bottom electrode will induce the symmetric Schottky contact in Pt/undoped ZnO nanorod interfaces. In addition, for ZnO thin film, it was found that Pt as the bottom electrode gives rise to better polarization than those in samples with indium tin oxide (ITO) and Au bottom electrode, as the gold electrode may induce Ohm contact interface with the ZnO surface. − In addition, it is found this thin Pt layer does not play a role in promoting growth on the substrate; it does not hinder the growth of ZnO on the spinel substrate either.…”