Single-crystal fibers represent perhaps one of the most underexplored areas of material science. Despite some early interest and excitement 30 years ago, the lack of immediate applications led to a decline in research activity, and until recently, little was known about their growth behavior and properties. During the past few years single-crystal fiber research has been revived and preliminary results have stimulated considerable interest in the scientific community.
At present, the most extensive and broadly based single-crystal fiber program is at Stanford University, where the focus has been on studying fibers for optical applications. This program emerged from a desire to combine the light-guiding properties of fiber geometries with the unique physical properties of crystalline materials, as was done during the last decade for glass fiber applications. Such materials could lead to a range of novel devices with higher efficiencies than possible in bulk crystals. But single-crystal fiber growth technology may have an even broader applicability. While single-crystal fibers of semiconductor, superconductor, and high strength materials could play an important role in future device applications, an important current use for the single-crystal fiber growth technology is in preparing single crystals of a wide variety of materials for property evaluation. Fiber crystals may have much higher crystalline perfection than bulk crystals of the same composition, making them useful for studying the intrinsic properties of a material and for improving device performance. Other areas of interest which have been identified include metastable phase formation and the growth of oriented ferroic domain and multiphase structures.