Stability of amorphous structures with voids

Stability of Amorphous Structures with Voids

We incorporate the role of free volume in the density function of the amorphous structure and study its effects on the stability of such structures. The Density Functional Theory is used to explore this “Free Volume Model” of the supercooled structures. The Free energy minimization is carried out using the void concentration as a variational parameter. A critical value of this concentration exi...

Static and dynamic properties of hydrogenated amorphous silicon with voids

We have employed ab initio techniques to study the structure and dynamics of voids in amorphous Si and hydrogenated amorphous silicon. Reconstruction effects at void surfaces and dynamical effects associated with H are particularly emphasized. We introduce unbonded H into the network, track its diffusive motion, and note a strong tendency for H to attack strained structures in the network. We c...

Approximate ab initio calculation of vibrational properties of hydrogenated amorphous silicon with inner voids

We have performed an approximate ab initio calculation of vibrational properties of hydrogenated amorphous silicon (a-Si:H) using a molecular dynamics method. A 216-atom model for pure amorphous silicon (a-Si) has been employed as a starting point for our a-Si:H models with voids that were made by removing a cluster of silicon atoms out of the bulk and terminating the resulting dangling bonds w...

Multilayered Amorphous Silicon Structures

Computer simulation of low-energy excitations in amorphous silicon with voids

We use empirical molecular dynamics technique to investigate the low-energy vibrations in a large 4096 atom model for pure amorphous silicon and a set of models with voids of di€erent size based on it. Numerical vibrational eigenvalues and eigenvectors for our models are obtained by exact diagonalization of their dynamical matrices. Our calculations show that localized low-energy vibrational ex...