Reliability Enhancement of Germanium Nanowires Using Graphene as a Protective Layer: Aspect of Thermal Stability

Abstract: We synthesized thermally stable graphene-covered Ge nanowires (Ge@G) and applied them in field emission devices. The Ge@G nanowires were prepared by sequential growth of the Ge nanowires and graphene shells in a single chamber. As a result of the thermal treatment experiments, Ge@G nanowires were much more stable than pure Ge nanowires, maintaining their shape at high temperatures up to 850 °C. To compare with pure Ge nanowires, field emission devices based on the Ge@G nanowires were fabricated; they clearly exhibited enhanced thermal reliability. Moreover, field emission characteristics yielded the highest field enhancement factor (~2298) yet reported for this type of device, and also had low turn-on voltage. Our proposed approach for the application of graphene as a protective layer for a semiconductor nanowire is an efficient way to enhance the thermal reliability of nanomaterials.