Multicolor graphene nanoribbon/semiconductor nanowire heterojunction light-emitting diodes

We report novel graphene nanoribbon (GNR)/semiconductor nanowire (SNW) heterojunction light-emitting diodes (LEDs) for the first time. In the device, the GNR and SNW have face-to-face contact with each other, which has the merits of a larger active region and smaller series resistance, and may benefit high-efficiency electroluminescence and even electrically driven lasers in the future. ZnO, CdS, and CdSe NWs were employed in our case. At forward biases, the GNR/SNW heterjunction LEDs could emit light with wavelengths varying from ultraviolet (380 nm) to green (513 nm) to red (705 nm), which were determined by the band-gaps of the involved SNWs. The mechanism of light emitting for the GNR/SNW heterojunction LEDs was discussed. Our work opens new routes to developing diverse graphene-based nano-optoelectronic devices, which are basic components in integrated optoelectronic system. Besides, the novel graphene/SNW hybrid devices, by taking advantage of both graphene and SNW, will be promising candidates for use in applications such as high-sensitivity sensor and transparent flexible devices in the future.