| Germanium nanowires are grown utilizing a vapor-liquid-solid mechanism in a home-built, hot-wall chemical vapor deposition reactor. These wires are of particular scientific and technological interest due to their relatively low growth temperature, which allows them to be grown on a wide variety of substrates. The wires are fully characterized, utilizing electron microscope techniques, EDX, XPS, RBS, XRD, and electrical measurements. We demonstrate the first growth of germanium nanowires directly on a flexible polymer substrate. An investigation into the growth rate of nanowires reveals that their nucleation cannot be described by a simple diffusion-limited model; a more complicated surface-limited kinetics model must be applied to fully describe growth. We explore the passivation of nanowires, focusing on the deposition of thin-films of robust oxides utilizing atomic layer deposition. Initial electrical measurements are investigated to gain some understanding as to the electrical properties of our wires. We present a novel organic-inorganic heterojunction photovoltaic cell, developed from germanium nanowires and poly (3-hexylthiophene), and demonstrate an increase in external quantum efficiency of the device with the inclusion of the germanium nanowires. |
