Investigation of condensation and evaporation of alkali halide crystals by molecular beam methods XIII. Development of two-dimensional islands on the (100) surface of KCl

Abstract

The development of size and shape of two-dimensional islands on the (100) surface of KCl is studied experimentally for T = 593 K and saturation ratios S = 1.12−5.97. From the equilibrium shape of small islands, the anisotropy of the ledge energy is derived. A comparison of experimental shapes with computer simulations of the growth of two-dimensional islands leads to a surface diffusion length of λ = Dτ = 0.15 μm . A ledge diffusion coefficient of D e = 7 × 10 −11 cm 2 s −1 and a jump frequency Γ e = 1.4 × 10 5 s −1 can be estimated for T = 593 K. The transition of molecules from the terrace to the steps is found to be unhampered.