Abstract
We present a quantitative analysis of layer-by-layer growth in pulsed laser deposition using homoepitaxy of SrTiO$_3$ as a prototype perovskite. The analysis of time-dependent coverages extracted from single shot surface x-ray diffraction transients shows that pulsed laser deposition consists of two phases that occur before and after crystallization on vastly different time scales. The non-equilibrium processes during and immediately after the arrival of the laser plume represent the primary mechanism for interlayer transport before crystallization that is completed on $\mu$s-range or faster time scales. Interlayer transport slows down dramatically after crystallization because it is driven only by sluggish thermally activated processes. The thermal interlayer transport represent a small fraction of total interlayer transport that decreases with the laser repetition rate. This analysis shows the energetic species that are present only during the plume arrival to be orders of magnitude more effective than thermal processes in promoting interlayer transport that is the key to the ability of pulsed laser deposition to produce sharp interfaces in both homo and heteroepitaxial growth of oxide films.
