Semiconductor Nanowires for Nanoscale Science and Technology Lincoln Lauhon Department of Chemistry, Harvard University Recent decades have witnessed tremendous advances in our capability to design and probe materials on ever smaller length scales. Even the manipulation of individual atoms is becoming routine. This progress has generated substantial opportunities for both the fundamental study and technological application of nanostructured materials. In particular, one-dimensional nanorods and nanotubes provide physicists with new means to explore the physics of electrons in low-dimensional systems and are viable components of emerging nanotechnologies. I will describe the synthesis of novel semiconductor nanowire heterostructures, their electrical and optical characterization, and the fabrication of nanoscale devices such as field-effect transistors and light emitting diodes. Nanowire heterostructures can also be viewed as nanoscale laboratories in which the experiment is 'built' from the nanoscale up. I will highlight new opportunities for the study of the electronic, magnetic, and optical properties of low-dimensional systems that have been created by recent advances in materials synthesis.