Variations in shapes of outgrowths on a tungsten tip during growth in an electric field

Continuous-mode field-desorption microscopy was used to study the shape of thermal-field outgrowths on the (001) face of a tungsten tip. It is shown that the shape and faceting of the lateral surface of an outgrowth change with its height, which can be explained by reconstruction of the lateral surface of the outgrowth due to a gradual decrease in the field intensity in the bottom part of the outgrowth during its growth. The reconstruction occurs because, at high field intensity, the shape and faceting are determined by the kinetics of growth, whereas at low field intensity they are determined by the minimum free energy.