Vacancy island creation and coalescence using automated scanning tunneling microscopy

We demonstrate that scanning tunneling microscope tip-surface crash events can be utilized as an efficient means for the creation of predefined island configurations for diffusion studies. Using this method, islands of varying size can be created and placed in close proximity, increasing the probability of initiating and observing coalescence events. Data obtained from crash initiated events on a Ag(111) surface are presented. Relaxation time exponents extracted from these data confirm that our method gives results consistent with previous, sputter-obtained island coalescence studies. We also describe an instrument-control routine developed for these measurements that utilizes commercial imaging and off-the-shelf automation software to automate the tracking of islands or other features by the microscope.