Implementation and optimization of a scanning Joule expansion microscope for the study of small conducting gold wires

In order to study heating phenomena with submicrometer spatial resolution, we have implemented a scanning Joule expansion microscope (SJEM). When comp ared to scanning thermal microscopy (SThM), which requires the microfabrica tion of thermal probes, SJEM has superior spatial resolution and can be imp lemented more easily since no special tips or cantilevers have to be fabric ated. Our SJEM measurements on small gold wires reveal that electrostatic f orce interactions between sample and tip can strongly affect the SJEM image s. Therefore, we have identified the relevant parameters, in particular the cantilever stiffness, which have to be optimized to obtain reliable result s. The temperature profile in the gold wires can be fitted to theoretical m odel calculations. (C) 2000 Published by Elsevier Science B.V. All rights r eserved.