Controlling nanowire structures through real time growth studies

In situ electron microscopy can be used to visualize the physical processes that control the growth of Si and Ge nanowires through the vapor-liquid-solid mechanism. Images and movies are recorded in a transmission electron microscope that has capabilities for depositing catalysts onto a sample and for introducing chemical vapor deposition precursor gases while the sample remains under observation. This technique allows us to measure nucleation, catalyst stability, surface structure and growth kinetics, in some cases confirming existing models and in other cases producing unexpected results and suggesting approaches toward growing novel structures. We will show that nanowire formation provides a unique window into the fundamentals of crystal growth as well as an opportunity to fabricate precisely controlled structures for novel applications. © 2010 IOP Publishing Ltd.