DOI link for Historical Perspective
Historical Perspective book
The predecessor to the nanowires is the whiskers of metallic and nonmetallic single crystals, which received that name due to their appearance. One-dimensional anisotropic crystals or whiskers were found in natural ores in the 1500s. Growth of silver whiskers from rocks in the 1600s was thought to be similar to the growth of grass [1,2]. In the mid-twentieth century, intensive research work at the Bell Telephone Laboratories led to the laboratory preparation of whiskers of several materials. Early studies included the preparation and characterization of B, B4C, C, Al2O3, SiC, and Si3N4; these whiskers were micron-sized (width or diameter) and exhibited high strengths of the order of 106 pounds per square inch (psi) . The primary motivation to study them was their potential as a reinforcing additive for metals and plastics. Preparation of silicon whiskers and the vapor-liquid-solid (VLS) concept were rst introduced by R.S. Wagner in a series of publications in the 1960s [3-6]. Since then, in the same decade, VLS technique was used to grow several other materials such as Al2O3, boron, GaAs, GaP, GaAs1−xPx, Ge, MgO, NiBr2, NiO, selenium, and SiC as cataloged in Ref. .