Working on the nanoscale can be tedious as the visualization of such small scales alone is a task on its own. Nature, however, sometimes surprises with self-assembly processes that can be exploited for advanced material production. In this talk the so-called heteroepitaxial growth of germanium type quantum dots on silicon type substrates is introduced. It is shown how continuum models can be used for a realistic description of the Ostwald ripening type process. A long-wave approximation leads to a fourth order quasi-linear partial dierential equation that reflects the temporal evolution of the growing and ripening surface. A trigonometric Fourier interpolant is used to treat the spatial discretization and different time-stepping methods that base on an explicit-implicit splitting are tested on the model. In particular, we will show that exponential time differencing methods are suitable for accurate and ecient in time calculations.