Microstructural analysis of nanostructured amorphous silicon–germanium alloys: Numerical modeling

Effect of low-temperature annealing on void-related microstructure in amorphous silicon: A computational study

“…In the intervening decades, a number of experimental techniques, ranging from small-angle x-ray scattering (SAXS), 4 spectroscopic ellipsometry (SE), Fourier transform infrared spectroscopy (FTIR), 5 and effusion of hydrogen and implanted-helium measurements 6 in a-Si:H to nuclear magnetic resonance (NMR), 7 provided an impressive database of experimental information on structural properties of a-Si and its hydrogenated counterpart. By contrast, until recently, 8 computational efforts [9][10][11][12] to address structural and electronic properties of a-Si have been mostly limited to results obtained from small atomistic models, consisting of a few to several hundreds of atoms, depending upon the quantum-mechanical or classical nature of atomic interactions employed in building those models. Thus, the computational modeling of largescale inhomogeneities in amorphous networks, such as voids in a-Si and a-Ge, were particularly hindered in the past due to the absence of large realistic models, which were needed to take into account the size and the number density of the voids, as observed in SAXS, NMR and FTIR studies.…”

Small-angle x-ray scattering in amorphous silicon: A computational study

“…In this paper, we address the morphology of voids in a-Si with particular emphasis on the relationship between the (simulated) intensity from SAXS and the shape, size, density, and the spatial distribution of the voids in amorphous silicon. While the problem has been studied extensively using experimental SAXS data for a-Si and a-Si:H, [17][18][19][20] there exist only a few computational studies 21,22 that have attempted to address the problem from an atomistic point of view using rather small models of a-Si, containing only 500 to 4000 atoms. Since the information that resides in the small-angle region of reciprocal space is connected to real space via the Fourier transformation, it is necessary to have a significantly large model to include any structural correlations that may originate from distant atoms in order to produce the correct long-wavelength behavior of the scattering intensity.…”