Now showing items 7139-7158 of 22915

    • Exciton dissociation in the presence of phonons : a reduced hierarchy equations of motion approach 

      Yao, Yao; Yang, Wenchao; Zhao, Yang (2014)
      Combining the reduced hierarchy equations of motion (HEOM) approach with the Wigner-function formalism, we investigate nonperturbatively exciton dissociation under the influence of a phonon bath in an organic heterojunction. ...
    • Exciton dynamics : ultrafast exciton dynamics and two-photon pumped lasing from ZnSe nanowires 

      Xing, Guichuan; Luo, Jingshan; Li, Hongxing; Wu, Bo; Liu, Xinfeng; Huan, Alfred Cheng Hon; Fan, Hong Jin; Sum, Tze Chien (2013)
      The commonly accepted paradigm that the higher pump intensities needed for two photon excitation (TPE) correspond to a higher exciton density threshold for two-photon pumped lasing (nth) is re-examined by T.-C. Sum and ...
    • Exciton dynamics in colloidal quantum-dot leds under active device operations 

      Shendre, Sushant; Sharma, Vijay Kumar; Dang, Cuong; Demir, Hilmi Volkan (2018)
      Colloidal quantum-dot light-emitting diodes (QLEDs) are lucrative options for color-pure lighting sources. To achieve high-performance QLEDs, besides developing high-efficiency quantum dots (QDs), it is essential to ...
    • Exciton-phonon coupling in individual ZnTe nanorods studied by resonant Raman spectroscopy 

      Zhang, Q.; Zhang, J.; Utama, M. I. B.; Peng, B.; Mata, Maria de la; Arbiol, Jordi; Xiong, Qihua (2012)
      The exciton-phonon coupling in high-quality cubic phase zinc telluride (ZnTe) nanorods (NRs) is investigated by resonant micro-Raman spectroscopy near the direct bandgap of ZnTe. The scattering cross section of longitudinal ...
    • Exciton-photon correlations in bosonic condensates of exciton-polaritons 

      Kavokin, Alexey V.; Sheremet, Alexandra S.; Shelykh, Ivan A.; Lagoudakis, Pavlos G.; Rubo, Yuri G. (2015)
      Exciton-polaritons are mixed light-matter quasiparticles. We have developed a statistical model describing stochastic exciton-photon transitions within a condensate of exciton polaritons. We show that the exciton-photon ...
    • An exciton-polariton bolometer for terahertz radiation detection 

      Paschos, G. G.; Liew, Timothy Chi Hin; Hatzopoulos, Z.; Kavokin, A. V.; Savvidis, P. G.; Deligeorgis, G. (2018)
      We experimentally investigate the feasibility of a bolometric device based on exciton-polaritons. Initial measurements presented in this work show that heating – via thermal expansion and bandgap renormalization – modifies ...
    • Exciton-polariton laser diodes 

      Amthor, M.; Fischer, J.; Savenko, I. G.; Shelykh, I. A.; Chernenko, A.; Rahimi-Iman, A.; Kulakovskii, V. D.; Reitzenstein, S.; Kim, N. Y.; Durnev, M.; Kavokin, A. V.; Yamamoto, Y.; Forchel, A.; Kamp, M.; Schneider, C.; Höfling, S. (2014)
      Despite their name polariton lasers do not rely on stimulated emission of cavity photons. The less stringent threshold conditions are the cause that bosonic polariton lasers can outperform standard lasers in terms of their ...
    • Exciton-polariton lasers in magnetic fields 

      Schneider, C.; Fischer, J.; Amthor, Matthias; Brodbeck, S.; Savenko, I. G.; Shelykh, I. A.; Chernenko, A.; Rahimi-Iman, A.; Kulakovskii, V. D.; Reitzenstein, S.; Kim, N. Y.; Durnev, M.; Kavokin, A. V.; Yamamoto, Y.; Forchel, A.; Kamp, M.; Höfling, S. (2014)
      Polariton lasers do not rely on stimulated emission of cavity photons, which sets stringent conditions on the threshold current in a conventional laser. Indeed, it has been demonstrated in optically pumped systems, that ...
    • Exciton-polariton oscillations in real space 

      Liew, Timothy Chi Hin; Rubo, Y. G.; Kavokin, A. V. (2014)
      We introduce and model spin-Rabi oscillations based on exciton-polaritons in semiconductor microcavities. The phase and polarization of oscillations can be controlled by resonant coherent pulses and the propagation of ...
    • Exciton-polariton quantum gates based on continuous variables 

      Kyriienko, O.; Liew, Timothy Chi Hin (2016)
      We propose a continuous-variable analog of quantum controlled-not gates based on a system of exciton polaritons in semiconductor microcavities. This can be realized by engineering a parametric interaction between control ...
    • Excitonic bandgap dependence on stacking configuration in four layer graphene 

      Liu, Y. P.; Goolaup, Sarjoosing; Lew, Wen Siang; Purnama, Indra; Sekhar, Murapaka Chandra; Zhou, T. J.; Wong, S. K. (2013)
      Different crystallographic stacking configurations in graphene provide an additional degree of freedom in the electronic structure. We have conducted systematic investigations of the transport properties of ABAB- and ...
    • Excitonic energy transfer dynamics in hybrid organic/inorganic nanocomposites at high loading levels 

      Guzelturk, Burak; Martinez, Pedro-Ludwig Hernandez; Tuncel, Donus; Demir, Hilmi Volkan (2012)
      Temperature dependent exciton migration in the hybrid nanocomposites of conjugated polymers chemically integrated with quantum dots is studied at high loading levels. The underlying interplay between the exciton transfer ...
    • Excitonic energy transfer in light-harvesting complexes in purple bacteria 

      Ye, Jun; Sun, Kewei; Zhao, Yang; Yu, Yunjin; Lee, Chee Kong; Cao, Jianshu (2012)
      Two distinct approaches, the Frenkel-Dirac time-dependent variation and the Haken-Strobl model, are adopted to study energy transfer dynamics in single-ring and double-ring lightharvesting ...
    • Excitonic enhancement of nonradiative energy transfer from a quantum well in the optical near field of energy gradient quantum dots 

      Nizamoglu, Sedat; Hernández-Martínez, Pedro Ludwig; Mutlugun, Evren; Karatay, Durmus Ugur; Demir, Hilmi Volkan (2012)
      We report strong exciton migration with an efficiency of 83.3% from a violet-emitting epitaxial quantum well (QW) to an energy gradient colloidal construct of layered green- and red-emitting nanocrystal quantum dots (NQDs) ...
    • Excitonic enhancement of nonradiative energy transfer to bulk silicon with the hybridization of cascaded quantum dots 

      Yeltik, Aydan; Guzelturk, Burak; Hernandez-Martinez, Pedro Ludwig; Akhavan, Shahab; Demir, Hilmi Volkan (2013)
      We report enhanced sensitization of silicon through nonradiative energy transfer (NRET) of the excitons in an energy-gradient structure composed of a cascaded bilayer of green- and red-emitting CdTe quantum dots (QDs) on ...
    • Excitonic photoluminescence from nanodisc states in graphene oxides 

      Kozawa, Daichi; Zhu, Xi; Miyauchi, Yuhei; Mouri, Shinichiro; Ichida, Masao; Su, Haibin; Matsuda, Kazunari (2014)
      The origin of near-infrared (NIR) luminescence from graphene oxide (GO) is investigated by photoluminescence (PL) excitation spectroscopy, time-resolved PL spectroscopy, and density functional theory based many body ...
    • Excitonic properties of graphene-based materials 

      Wang, Min; Li, Chang Ming (2012)
      First-principle density functional theory (DFT) calculations with quasiparticle corrections and many body effects are performed to study the electronic and optical properties of graphene-based materials. This review ...
    • Excitonics of semiconductor quantum dots and wires for lighting and displays 

      Guzelturk, Burak; Martinez, Pedro Ludwig Hernandez; Zhang, Qing; Xiong, Qihua; Sun, Handong; Sun, Xiao Wei; Govorov, Alexander O.; Demir, Hilmi Volkan (2014)
      In the past two decades, semiconductor quantum dots and wires have developed into new, promising classes of materials for next-generation lighting and display systems due to their superior optical properties. In particular, ...
    • Excitons of edge and surface functionalized graphene nanoribbons 

      Zhu, Xi; Su, Haibin (2010)
      We apply density functional theory to study the optical properties of armchair graphene nanoribbons (AGNRs) functionalized from both edge and surface employing quasiparticle corrections and many body, that is, electron−hole, ...
    • The Excluded Minors for Isometric Realizability in the Plane 

      Fiorini, Samuel; Huynh, Tony; Joret, Gwenaël; Varvitsiotis, Antonios (2017)
      Let $G$ be a graph and $p \in [1, \infty]$. The parameter $f_p(G)$ is the least integer $k$ such that for all $m$ and all vectors $(r_v)_{v \in V(G)} \subseteq \mathbb{R}^m$, there exist vectors $(q_v)_{v \in V(G)} \subseteq ...