GRYSTALLOGRAPHIC EVALUATION OF MESOSCOPIC PARTICLES FORMED BY FGE-TECHNIQUE

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(1)Time-dependence of rate constant for crystallization process of amorphous Sb nano-particlesAmorphopus Sb nano-particles are formed by the FGE technique under the following conditions as 6.9m/s of Ar gas velocity and 1.7kPa of the gas pressure. The particles are collected on amorphous carbon films. Two kinds of annealing are carried out in vacuum (a) pre-annealing at 70ﾟC for 6hs followed by the annealing at 150ﾟC for various durations and (b) annealing at 150ﾟC for various durations without preannealing. Time-dependence of crystallization ratio was investigated through the dark field electron microscopic image of annealed specimens. Crystallization ratio Pc can be written by the following equation (1) from the view point of homogeneous reaction of first order,Ln(1-Pc)=Rc・t (1)where Rc represents the rate constant of crystallization. In the case of above (b) Rc does not keep constant and shows a gradual alowing down of crystallization in every particle size. On the other hand, Rc keeps constant for long time in case of (a). Furthermore, Rc decreases with the decrease of the particle size D.The different feature shown in two cases of (a) and (b) can be explained by a reluxation of amorphous structure.(2)Particle size distribution and its control of nano-particles formed by FGE techniqueAntimony was evaporated in the flowing He gas with the velocity of 6m/s. Particle size distribution fits satisfactorily a Gaussian. Mean particle size decreases from 9.5nm to 7.0nm with increasing of evaporation temperature from 850ﾟC to 900ﾟC.This tendency may reflect a critical nucleus size.