Oxygen migration, agglomeration, and trapping: key factors for the morphology of the Si-SiO(2) interface

Stress-Induced Acceleration and Ordering in Solid-State Dewetting

We report on the influence of elastic strain on solid-state dewetting. Using continuum modeling, we first study the consequences of elastic stress on the pinching of the film away from the triple line during dewetting. We find that elastic stress in the solid film decreases both the time and the distance at which the film pinches in such a way that the dewetting front is accelerated. In addition, the spatial organization of islands emerging from the dewetting process is affected by strain. As an example, we demonstrate that ordered arrays of quantum dots can be achieved from solid-state dewetting of a square island in the presence of elastic stress.

Exploring the initiation of fiber fuse

We report an investigation of conditions for the initiation of fiber fuse (IFF), a kind of catastrophic damage that troubles all kinds of optical fibers, in silica-based optical fibers. The fibers of different chemical compositions were processed and tested in controlled conditions without mechanical damages before the IFF. For all the fibers of IFF, the same correlation between the critical temperatures and the optical powers transmitted therein was revealed for the first time. The fibers of different chemical compositions exhibited different resistances to the IFF under the threshold powers for propagation of fiber fuses. The results offered promise for predicting fiber fuses in optical fiber systems, which could facilitate avoiding catastrophic losses. They could direct the optimization of fiber production technologies for suppressing the damages, as well as open a new path towards controlled utilization of fiber fuse in in-fiber microstructure fabrication.

Role of N defects on thermally induced atomic-scale structural changes in transition-metal nitrides

Transition-metal nitrides (TMN) have exceptional stability, which underlies their use in various applications. Here, we study the role of N point defects on the stability of prototype TMNs using first-principles calculations. We find that distinct regimes for TMN changes relate to specific atomic-scale mechanisms, namely, diffusion of N interstitials (I(N)), of I(N) pairs, and of N vacancies. The activation of these processes occurs sequentially as the temperature is raised in a range of several hundreds of degrees, accounting for observed TMN changes under widely different conditions.