1
|
Wang Y, Li Z, Bai Y, Wang Y. Increasing the Light Extraction Efficiency of Organic Light-Emitting Devices by Electrochemically Corroded Patterned Substrates. MICROMACHINES 2023; 15:67. [PMID: 38258187 PMCID: PMC10821355 DOI: 10.3390/mi15010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024]
Abstract
A substrate with microstructure can increase the light extraction efficiency of OLEDs. However, the present preparation methods for micro- and nanostructures are not suited for broad-area manufacturing. In this research, we suggested an electrochemical etching approach to patterning Si substrates and effectively generated a vast area of micro-/nanostructures on the surface of Si. We created OLEDs using this patterned substrate. It was discovered through this study that when the current density is 100 mA/cm2, the brightness increases by 1.67 times and the efficiency increases by 1.43 times, over a planar equivalent. In the future, this electrochemical etching process for patterned silicon substrates might give rise to a new approach to the large-scale manufacture of microstructured silicon substrates.
Collapse
Affiliation(s)
- Yang Wang
- School of Electronic Information Engineering, Changchun University of Science and Technology, Changchun 130022, China
| | | | | | | |
Collapse
|
2
|
Bai Y, Chuai Y, Wang Y, Wang Y. Higher Light Extraction Efficiency in Organic Light-Emitting Devices by Employing 2D Periodic Corrugation. Front Chem 2022; 9:807867. [PMID: 35071189 PMCID: PMC8766635 DOI: 10.3389/fchem.2021.807867] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 12/01/2022] Open
Abstract
Photons trapped in the form of waveguide (WG) modes associated with the organic–organic interface and in the form of surface plasmon polariton (SPP) modes associated with the metallic electrode–organic interface result in a large energy loss in organic light-emitting devices (OLEDs). Introducing gratings onto the metallic electrode is especially crucial for recovering the power lost to the associated SPP modes. In our research, we demonstrate the efficient outcoupling of SPP modes in TE mode by two-dimensional (2D) grating, which cannot excited in one-dimensional (1D) grating OLED. This causes a 62.5% increase in efficiency from 2D grating OLED than 1D grating OLED. The efficient outcoupling of the WG and SPP modes is verified by the numerical simulation of both the emission spectra and the field distribution.
Collapse
Affiliation(s)
- Yu Bai
- Changchun University of Science and Technology, Changchun, China
| | - Yahui Chuai
- Changchun University of Science and Technology, Changchun, China
| | - Yang Wang
- Changchun University of Science and Technology, Changchun, China
| | - Yingzhi Wang
- Changchun University of Science and Technology, Changchun, China
| |
Collapse
|
3
|
Yanagi K, Okada R, Ichinose Y, Yomogida Y, Katsutani F, Gao W, Kono J. Intersubband plasmons in the quantum limit in gated and aligned carbon nanotubes. Nat Commun 2018; 9:1121. [PMID: 29549341 PMCID: PMC5856781 DOI: 10.1038/s41467-018-03381-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/06/2018] [Indexed: 11/09/2022] Open
Abstract
Confined electrons collectively oscillate in response to light, resulting in a plasmon resonance whose frequency is determined by the electron density and the size and shape of the confinement structure. Plasmons in metallic particles typically occur in the classical regime where the characteristic quantum level spacing is negligibly small compared to the plasma frequency. In doped semiconductor quantum wells, quantum plasmon excitations can be observed, where the quantization energy exceeds the plasma frequency. Such intersubband plasmons occur in the mid- and far-infrared ranges and exhibit a variety of dynamic many-body effects. Here, we report the observation of intersubband plasmons in carbon nanotubes, where both the quantization and plasma frequencies are larger than those of typical quantum wells by three orders of magnitude. As a result, we observed a pronounced absorption peak in the near-infrared. Specifically, we observed the near-infrared plasmon peak in gated films of aligned single-wall carbon nanotubes only for probe light polarized perpendicular to the nanotube axis and only when carriers are present either in the conduction or valence band. Both the intensity and frequency of the peak were found to increase with the carrier density, consistent with the plasmonic nature of the resonance. Our observation of gate-controlled quantum plasmons in aligned carbon nanotubes will not only pave the way for the development of carbon-based near-infrared optoelectronic devices but also allow us to study the collective dynamic response of interacting electrons in one dimension.
Collapse
Affiliation(s)
- Kazuhiro Yanagi
- Department of Physics, Tokyo Metropolitan University, Tokyo, 192-0397, Japan.
| | - Ryotaro Okada
- Department of Physics, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Yota Ichinose
- Department of Physics, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Yohei Yomogida
- Department of Physics, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Fumiya Katsutani
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, 77005, USA
| | - Weilu Gao
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, 77005, USA
| | - Junichiro Kono
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, 77005, USA. .,Department of Physics and Astronomy, Rice University, Houston, TX, 77005, USA. .,Department of Materials Science and Nanoengineering, Rice University, Houston, TX, 77005, USA.
| |
Collapse
|
4
|
Paspalakis E, Boviatsis J. Ultrashort electromagnetic pulse control of intersubband quantum well transitions. NANOSCALE RESEARCH LETTERS 2012; 7:478. [PMID: 22916956 PMCID: PMC3497868 DOI: 10.1186/1556-276x-7-478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 08/03/2012] [Indexed: 06/01/2023]
Abstract
: We study the creation of high-efficiency controlled population transfer in intersubband transitions of semiconductor quantum wells. We give emphasis to the case of interaction of the semiconductor quantum well with electromagnetic pulses with a duration of few cycles and even a single cycle. We numerically solve the effective nonlinear Bloch equations for a specific double GaAs/AlGaAs quantum well structure, taking into account the ultrashort nature of the applied field, and show that high-efficiency population inversion is possible for specific pulse areas. The dependence of the efficiency of population transfer on the electron sheet density and the carrier envelope phase of the pulse is also explored. For electromagnetic pulses with a duration of several cycles, we find that the change in the electron sheet density leads to a very different response of the population in the two subbands to pulse area. However, for pulses with a duration equal to or shorter than 3 cycles, we show that efficient population transfer between the two subbands is possible, independent of the value of electron sheet density, if the pulse area is Π.
Collapse
Affiliation(s)
- Emmanuel Paspalakis
- Materials Science Department, School of Natural Sciences, University of Patras, Patras, 26504, Greece
| | - John Boviatsis
- Technological and Educational Institute of Patras, Patras, 26334, Megalou Alexandrou 1, Greece
| |
Collapse
|
5
|
Dai J, Raikh ME, Shahbazyan TV. Two-electron linear intersubband light absorption in a biased quantum well. PHYSICAL REVIEW LETTERS 2006; 96:066803. [PMID: 16606029 DOI: 10.1103/physrevlett.96.066803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Indexed: 05/08/2023]
Abstract
We point out a novel manifestation of many-body correlations in the linear optical response of electrons confined in a quantum well. Namely, we demonstrate that along with the conventional absorption peak at a frequency omega close to the intersubband energy delta, there exists an additional peak at frequency h omega approximately = 2delta. This new peak is solely due to electron-electron interactions, and can be understood as excitation of two electrons by a single photon. The actual peak line shape is comprised of a sharp feature, due to excitation of pairs of intersubband plasmons, on top of a broader band due to absorption by two single-particle excitations. The two-plasmon contribution allows us to infer intersubband plasmon dispersion from linear absorption experiments.
Collapse
Affiliation(s)
- J Dai
- Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | |
Collapse
|
6
|
Dynes JF, Frogley MD, Beck M, Faist J, Phillips CC. ac Stark splitting and quantum interference with intersubband transitions in quantum wells. PHYSICAL REVIEW LETTERS 2005; 94:157403. [PMID: 15904187 DOI: 10.1103/physrevlett.94.157403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Indexed: 05/02/2023]
Abstract
Resonant optical coupling experiments have demonstrated coherent quantum interference between the Stark-split "dressed states" of a synthesized 3-level electronic system in a semiconductor quantum well. Analysis of the dephasing mechanisms reveals dipole selection rules closely analogous to those seen in atomic spectroscopy experiments. In this respect, these systems behave as "artificial atoms" for the purposes of observing a range of nonclassical coherent optical effects. The prospects for exploiting them for scalable quantum information processing applications are more promising than previous dephasing models would have predicted.
Collapse
Affiliation(s)
- J F Dynes
- Experimental Solid State Group, Department of Physics, Imperial College London, London SW7 2BZ, United Kingdom
| | | | | | | | | |
Collapse
|
7
|
Ning CZ. Two-photon lasers based on intersubband transitions in semiconductor quantum wells. PHYSICAL REVIEW LETTERS 2004; 93:187403. [PMID: 15525208 DOI: 10.1103/physrevlett.93.187403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Indexed: 05/24/2023]
Abstract
We propose to make a two-photon laser based on intersubband (sublevel) transitions in semiconductor nanostructures. The advantages and feasibility of such a two-photon laser are analyzed in detail using the density matrix approach. Both one-photon and two-photon gains in a three subband quantum well structure are studied on the same footing to show how the two-photon gain can be maximized, while the competing one-photon gain is minimized. The results show that a sufficient two-photon gain can be achieved to overcome one-photon competition and the loss of a conventional semiconductor cavity, making intersubband transitions one of the very few feasible approaches to two-photon lasing.
Collapse
Affiliation(s)
- C Z Ning
- Center for Nanotechnology, NASA Ames Research Center, Mail Stop N229-1, Moffett Field, CA 94035, USA.
| |
Collapse
|
8
|
Li J, Ning CZ. Induced transparency by intersubband plasmon coupling in a quantum well. PHYSICAL REVIEW LETTERS 2004; 93:087402. [PMID: 15447224 DOI: 10.1103/physrevlett.93.087402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Indexed: 05/24/2023]
Abstract
We study coupling of two intersubband plasmons associated with dipole-allowed cascading transitions in a quantum well. We show that the coupling can lead to the disappearance of the lower-energy resonance accompanied by an anticrossing behavior. Such coupling induced anomalies are of collective and resonant nature and provide the first example of Coulomb interaction induced transparency. Our numerical results from a microscopic theory are confirmed by an analytical model.
Collapse
Affiliation(s)
- Jianzhong Li
- Center for Nanotechnology, NASA Ames Research Center, Mail Stop N229-1, Moffett Field, CA 94035, USA.
| | | |
Collapse
|
9
|
Bao JM, Pfeiffer LN, West KW, Merlin R. Ultrafast dynamic control of spin and charge density oscillations in a GaAs quantum well. PHYSICAL REVIEW LETTERS 2004; 92:236601. [PMID: 15245181 DOI: 10.1103/physrevlett.92.236601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Indexed: 05/24/2023]
Abstract
We use subpicosecond laser pulses to generate and monitor in real time collective oscillations of electrons in a modulation-doped GaAs quantum well. The observed frequencies match those of intersubband spin- and charge-density excitations. Light couples to coherent density fluctuations through resonant stimulated Raman scattering. Because the spin- and charge-related modes obey different selection rules and resonant behavior, the amplitudes of the corresponding oscillations can be independently controlled by using shaped pulses of the proper polarization.
Collapse
Affiliation(s)
- J M Bao
- Focus Center and Department of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120, USA
| | | | | | | |
Collapse
|
10
|
Batista AA, Citrin DS. Rabi flopping in a two-level system with a time-dependent energy renormalization: intersubband transitions in quantum wells. PHYSICAL REVIEW LETTERS 2004; 92:127404. [PMID: 15089706 DOI: 10.1103/physrevlett.92.127404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Indexed: 05/24/2023]
Abstract
We obtain pulse-driven Rabi oscillations guided by a generalization of the rotating-wave approximation to include, in the optical-Bloch equations, two-level systems with a time-varying transition energy. We achieve this by using chirped pulses with the central frequency given by the time-varying transition energy. Using this approach, we predict Rabi oscillations in intersubband transitions in a two-subband n-type modulation-doped quantum well by taking into account the time-dependent intersubband energy-gap renormalization due to depolarization-shift effects. We obtain Rabi oscillations for jpi (j=0,1,2, ) pulses in the presence of dephasing.
Collapse
Affiliation(s)
- Adriano A Batista
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0250, USA
| | | |
Collapse
|