6.1 Introduction

The aerosol method of nano-scale materials production has been studied as early as the 1930's in which bismuth and zinc were evaporated in air at low pressures forming soot-like zincblack and bismuth fumes (Pfund, 1930, 1933). The first use of inert gases as an environment for evaporation of metals was accomplished in the early 1940's (Beek, et al., 1940, 1945), but at this time was used for thin film production. Further progress of nanomaterials production continued with the refinement of electron diffraction first proposed by Kikuchi (Kikuchi, 1928) and utilized by Miyaki (Miyaki, 1938) to understand the structure and morphology of nanometer-scale particles of Sb ₂O ₃ grown on Sb ₂S ₃. Later, Uyeda was able to observe the in situ growth of Ag particles from vapor using reflection high energy electron diffraction (RHEED) (Uyeda, 1942).

As transmission electron microscopes (TEM) became more accessible to the scientific community at large the growth of nano-scale material's study blossomed. Kimoto and colleagues in the early 1960's were the first to systematically study nanometer scale metal particles evaporated in argon gas at low pressures (Kimoto, et al., 1963). This first example of what has become known as the inert gas condensation (IGC) method showed that the average particle size varied from 10 to 100's of nanometers with variation of the initial argon pressure in the vacuum chamber from 1 to 30 mm Hg(1 mm Hg = 133.3224 Pa), respectively. In the 1970's and 1980's...