New breakthroughs in carbon nanotube light-emitting diodes

According to foreign media reports, carbon nanotubes emit light when they pass current. This phenomenon can be used to make future optoelectronic components, but the emitted light has excessive bandwidth, inhomogeneous light field and low luminous output. problem. Recently, IBM scientists have found ways to precisely control the luminescence of carbon nanotubes. This result means that the narrow-band carbon nanotubes (LEDs) and single-photon sources required for quantum optics applications are no longer a distant dream.

        The illuminating component mainly utilizes the recombination of electrons and holes to generate photons. Recently, Phaedon Avouris et al. at the IBM TJ Watson Research Center demonstrated that the use of clever component layouts can control charge carrier injection and photon generation in carbon tubes more accurately than ever before.

Device structure diagram

        Compared to previous nanotube illuminating components, IBM researchers have successfully increased the luminous efficiency of the predetermined area of ​​the diode by a factor of 1000, and the width of the emitted light spectrum has also narrowed, about one-tenth of the previous one. In addition, the component has a relatively low current threshold and consumes a lot less power, so it is less likely to generate heat.

Device structure diagram

        IBM's nanotube light-emitting diodes are first placed on a dielectric substrate with a carbon nanotube. The ends of the tube are connected to a metal electrode, and then the nanotube and metal electrode are covered with another dielectric material, and the dielectric is dielectric. Two gate electrodes are fabricated over the layers to define different spatial extents on the carbon nanotubes. If an electrically opposite bias is applied to the two gates, the corresponding two carbon tube locations underneath will be "doped" with oppositely charged carriers (ie, electrons and holes). At this point the diode is activated and the carriers will recombine with each other and emit photons from these two locations on the carbon tube.

        Scientists are currently planning to improve the layout of components. Avouris pointed out that the use of carbon nanotube arrays is expected to further optimize and customize the performance of positive components. See Nature Nanotechnology doi: 10.1038/nnano.2009.319 for details.