11
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Kinetics of Exciton Emission Patterns and Carrier Transport

      Preprint
      , , , ,

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          We report on the measurements of the kinetics of expanding and collapsing rings in the exciton emission pattern. The rings are found to preserve their integrity during expansion and collapse, indicating that the observed kinetics is controlled by charge carrier transport rather than by a much faster process of exciton production and decay. The relation between ring kinetics and carrier transport, revealed by our experiment and confirmed by comparison with a theoretical model, is used to determine electron and hole transport characteristics in a contactless fashion.

          Related collections

          Most cited references7

          • Record: found
          • Abstract: not found
          • Article: not found

          Coupled electron-hole transport

            Bookmark
            • Record: found
            • Abstract: found
            • Article: found
            Is Open Access

            Macroscopically ordered state in exciton system

            Macroscopically ordered arrays of vortices in quantum liquids, such as superconductors, He-II, and atom Bose-Einstein Condensates (BEC), demonstrate macroscopic coherence in flowing superfluids [1-4]. Despite of the rich variety of systems where quantum liquids reveal macroscopic ordering, experimental observation of a macroscopically ordered electronic state in semiconductors has remained a challenging unexplored problem. A system of excitons is a promising candidate for the realization of macroscopic ordering in a quantum liquid in semiconductors. An exciton is a bound pair of an electron and a hole. At low densities, it is a Bose quasi-particle. At low temperatures, of the order of a few Kelvins, excitons can form a quantum liquid, i.e., a statistically degenerate Bose gas and eventually BEC [5-9]. Here, we report the experimental observation of a macroscopically ordered state in an exciton system.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Coulomb Drag in the Exciton Regime in Electron-Hole Bilayers

              We report electrical transport measurements on GaAs/AlGaAs based electron-hole bilayers. These systems are expected to make a transition from a pair of weakly coupled two-dimensional systems to a strongly coupled exciton system as the barrier between the layers is reduced. Once excitons form, phenomena such as Bose-Einstein condensation of excitons could be observed. In our devices, electrons and holes are confined in double quantum wells, and carriers in the devices are induced with top and bottom gates leading to variable density in each layer. Separate contact to each layer allows Coulomb drag transport measurements where current is driven in one layer while voltage is measured in the other. Coulomb drag is sensitive to interlayer coupling and has been predicted to provide a strong signature of exciton condensation. Drag measurement on EHBLs with a 30 nm barrier are consistent with drag between two weakly coupled 2D Fermi systems where the drag decreases as the temperature is reduced. When the barrier is reduced to 20 nm, we observe a consistent increase in the drag resistance as the temperature is reduced. These results indicate the onset of a much stronger coupling between the electrons and holes which leads to exciton formation and possibly phenomena related to exciton condensation.
                Bookmark

                Author and article information

                Journal
                20 August 2009
                Article
                10.1103/PhysRevB.81.115320
                0908.2978
                16c1ab5f-5552-482e-aeaf-21d1f2213fde

                http://arxiv.org/licenses/nonexclusive-distrib/1.0/

                History
                Custom metadata
                Phys. Rev. B 81, 115320 (2010)
                6 pages, 4 figures
                cond-mat.mes-hall

                Comments

                Comment on this article