Nucleation and growth rate of a -Si alloys

From fitting the crystallization rate to an Arrhenius rate expression with a single activation energy we found that it is possible to distinguish a purely amorphous silicon sample from one having trace crystallinity. Whenever microcrystallites are present whether from heavy P doping or heat treatment, the ‘‘activation energy’’ is approximately 1 eV, whereas purely amorphous silicon has an activation energy of 3–4 eV. In other words, the exponent on time in the Avrami expression is different for the nucleation and growth processes.