Role of strain in interacting silicon nanoclusters

The possibility of controlling the optical transition probability between neighboring silicon nanoclusters (Si-NCs) constitutes nowadays an attractive prospect in nanophotonics and photovoltaics. In this work, by means of theoretical ab initio calculations, we investigate the effect of strain on the optoelectronic properties of Si-NCs pairs. We consider two sources of strain: the strain induced by an embedding SiO2 matrix and the strain generated by mutual NC-NC forces occurring at small distances. Independently on its source, we observe a fundamental impact of the strain on the orbital localization and, as a consequence, on the transition probability between energy states belonging or not to the same NC. The resulting picture allots to the structural strain a fundamental role in the NC-NC interaction mechanisms, suggesting the possibility of enabling a strain-controlled response in Si-NC ensembles.