CONTROLLED ELECTRICAL CONTACT OF A SCANNED PROBE TO NANOSTRUCTURES

An optically guided scanned probe has been used to establish electrica l contact with and obtain electrical characteristics of individual, id entifiable nanostructures. Previous reports of measurements of the ele ctrical characteristics of nanostructures have been obtained in vacuum and without knowledge or control of the amount of electrical contact. We describe new techniques for establishing controlled, nondestructiv e electrical contact to nanostructures in air that improve the reprodu cibility and interpretation of the electrical measurements. Repeated m easurements of current (I)-voltage (V) relations during controlled app roach of the probe tip to the sample surface permitted nondestructive establishment of electrical contact. The efficacy of the technique was determined by measuring the I-V characteristics of Schottky barriers as a function of temperature. An identifiable quantum dot resonant tun neling diode was then successfully characterized.