STRUCTURAL AND VIBRATIONAL

Structural information on hydrogenated amorphous silicon (a-Si:H) can take several forms.
From infrared (IR) spectroscopy, information on the different types of H bonding, and the total
amount of bonded H contained within the a-Si lattice, can easily be obtained. In some cases,
structural information can be obtained directly from IR analysis, but normally relating IR
analysis to the (micro) structure of the material requires additional kinds of measurements. One
scenario relates the information obtained from IR analysis directly to structural changes
occurring within the lattice, as observed for example by such measurements as film density
changes, H evolution measurements and scanning electron micrographs, and this approach will
be used in the present Datareview. On the other hand, structural information obtained from
Raman spectroscopy can stand alone, since this is thought to be one of the few measurements
that can uniquely determine the structure of the a-Si:H on the scale of short range order.
Whenever possible, attempts to relate the IR and Raman measurements will be made.