Atomistic Origin and Pressure Dependence of Band Gap Variation in Semiconductor Nanocrystals

We have investigated band gap variation of semiconductor nanocrystals based on the extension of the bond-order-length-strength (BOLS) correlation mechanism to the pressure domain with the local bond average (LBA) approach. An analytical solution has been developed to connect the band gap energy with the bonding identities by considering the joint effects of size and pressure and the nature of the bond involved, which is consistent with understanding the interdependence of these quantities and their common atomistic origin. It has been clarified that the bond contraction associated with the single bond energy strength originates with size- and pressure-induced change, leading to crystal potential variation. Theoretical results are in agreement with the experimental measurements.