This book covers virtually all aspects of semiconductor nanowires, from growth to related applications, in detail. First, it addresses nanowires' growth mechanism, one of the most important topics at the forefront of nanowire research. The focus then shifts to surface functionalization: nanowires have a high surface-to-volume ratio and thus are well-suited to surface modification, which effectively functionalizes them. The book also discusses the latest advances in the study of impurity doping, a crucial process in nanowires. In addition, considerable attention is paid to characterization techniques such as nanoscale and in situ methods, which are indispensable for understanding the novel properties of nanowires. Theoretical calculations are also essential to understanding nanowires' characteristics, particularly those that derive directly from their special nature as one-dimensional nanoscale structures. In closing, the book considers future applications of nanowire structures in devices such as FETs and lasers.