Thermal Annealing of Gas-Evaporated Ge Microcrystals: A Raman and Electron Microscopic Study

Effects of thermal annealing on gas-evaporated Ge microcrystals as small as 90 Â were investigated by Raman spectroscopy and electron microscopy. It is found that the size of microcrystals abruptly increases when they are annealed at 500°C, presumably due to the surface melting coalescence. The abrupt growth of microcrystals leads to an abrupt increase in the intensity of crystalline Raman signal. The close similarity between the spectral changes presently observed and those previously observed for a-Si and a-Ge films suggests that the crystallization process in so-called amorphous films can be well understood in terms of the growth of microcrystals. © 1987, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.