Growth of mesoscopic correlated droplet patterns by high-vacuum sublimation

Abstract

A novel growth mode, characterized by absence of grain coarsening, Ostwald ripening, and secondary nucleation, is observed for a polar conjugated molecule, viz. tris-(8-hydroxyquinoline) aluminum (III) ${(\mathrm{A}\mathrm{l}\mathrm{q}}_3),$ grown onto an apolar silicon substrate by high-vacuum sublimation. It results in correlated droplet patterns on a mesoscopic length scale with narrow size distribution, which can be tuned by means of the deposition time t and substrate temperature $T_s.$ A comprehensive analysis of the results is obtained on the basis of a capture zone model.