In 1916 he accidentally dipped his pen into a crucible of molten tin rather than his inkwell. 
When he immediately pulled out pen and discover that a thin thread of solidified metal was hanging from the nib. 
The nib was replaced by a capillary, and Czochralski verified that the crystallized metal was a single crystal. 

He published a paper on his discovery in 1918. The method was used for measuring the crystallization rate of metals.
In the late 40s, Gordon K. Teal and J.B. Little from Bell Labs used the method to grow single germanium crystals, 
leading to its use in semiconductor production.
The method is still in use to production of Monocrystalline silicon - the basic material in the production of 
integrated circuits and solar cells.