Previous research have posited that amorphous Selenium has a chain-like structure, independent of the manufacturing processes. However, a recent study in a collaboration between experimental teams from Stony Brook University and Oak Ridge National Laboratory found that the structure of amorphous Selenium (a-Se) films manufactured by vapor deposition (VD) and melt-quenched (MQ) processes are predominantly composed of ring-like and chain-like molecules, respectively. Given that no experimental technique is able to query the detailed three-dimensional atomic arrangements in glassy semiconductors, scientists are hoping that simulations can offer more evidence and structural detail.
Using ATK-ForceField, a tool specializing in large-scale atomistic modeling based on empirical potentials, scientists at QuantumWise were able to replicate the different manufacturing processes in a molecular dynamics simulation, using a reliable empirical three-body interatomic potential. Evidence for the ring-like molecular structure in the VD a-Se films was indeed obtained, confirming the experimental hypothesis.
The experiment-verified model and simulation results will help in process and device design in the future. This detailed knowledge of molecular arrangements is very useful for further investigations of electronic and transport properties using quantum simulations. The results of this paper will facilitate the investigation of correlations between structural and electronic properties and can be used as a basis to improve the preparation procedures for specific applications in a more scientific and efficient manner.
A. H. Goldan et al., "Molecular structure of vapor-deposited amorphous selenium", J. Appl. Phys. 120, 135101 (2016)