Abstract: A photonic crystal device includes a two-dimensional crystal including a gain medium and having a first photonic crystal resonator and a second photonic crystal resonator spaced apart from each other and a graphene layer disposed to cover a portion of the first photonic crystal resonator and not to cover the second photonic crystal resonator.

Abstract: A photonic crystal device includes a two-dimensional crystal including a gain medium and having a first photonic crystal resonator and a second photonic crystal resonator spaced apart from each other and a graphene layer disposed to cover a portion of the first photonic crystal resonator and not to cover the second photonic crystal resonator.

Abstract: The present invention generally relates to nanoscale wires and, in particular, to nanoscale wires with heterojunctions, such as tip-localized homo- or heterojunctions. In one aspect, the nanoscale wire may include a core, an inner shell surrounding the core, and an outer shell surrounding the inner shell. The outer shell may also contact the core, e.g., at an end portion of the nanoscale wire. In some cases, such nanoscale wires may be used as electrical devices. For example a p-n junction may be created where the inner shell is electrically insulating, and the core and the outer shell are p-doped and n-doped. Other aspects of the present invention generally relate to methods of making or using such nanoscale wires, devices, or kits including such nanoscale wires, or the like.