Published online by Cambridge University Press: 01 February 2011
A series of multilayer structures consisting of alternating layers of hydrogenated amorphous silicon (a-Si:H) and amorphous silicon nitride (a-SiNx:H) was fabricated using plasma enhanced chemical vapor deposition. The overall thickness and a-Si:H-to-a-SiNx:H ratio was kept constant for the different multilayer samples fabricated. A blue shift of the optical bandgap was observed with decreasing a-Si:H well layer thickness. High-Resolution Transmission Electron Microscopy was used to estimate the abruptness of the layer-to-layer transitions. The thickness of the interface mixing layer for transitions from a-Si:H to a-SiNx:H was estimated to be 0.5 − 1 nm, while for the reverse transition a thickness of 2-2.5 nm was found. Results from Fourier Transform Infrared Spectroscopy support the found thickness range.