Superradiant emission from self-assembled light emitters: From molecules to quantum dots
- PDF / 8,160,859 Bytes
- 9 Pages / 585 x 783 pts Page_size
- 29 Downloads / 154 Views
oduction Light is a cross-disciplinary subject that has fascinated scientists for centuries and has revolutionized society through medicine, transoceanic communications, high-speed Inter net, and high-performance computing, just to mention a few examples. Disruptive progress in the development of light sources has been tightly linked to innovations in the nanoscale engineering of materials. In 2000, the Nobel Prize in Physics was awarded jointly to H. Kroemer and Z.I. Alferov, for “developing semiconductor heterostructures used in high-speed-photography and optoelectronics,”1 a breakthrough that was enabled by the monolayer thickness control achieved in epitaxial growth methods. Likewise, efficient blue gallium nitride (GaN) light-emitting devices (LEDs) (I. Akasaki, H. Amano, and S. Nakamura, Nobel Prize in Physics in 20142) have become possible once the quality of GaN layers was much improved by introducing an AlN buffer layer, which mitigated the effect of the lattice mismatch with the substrate and prevented formation of defects and dislocations. Quantum dots (QDs),3 nanometer-sized semiconductor crystals with confined electronic wavefunctions are outstanding
light emitters with high efficiency and tunability in their emission energy. Colloidal synthesis of semiconductor nanocrystals (often called colloidal QDs) has undergone tremendous progress and become a viable alternative to fully solid-state growth pathways such as ultrahigh-vacuum molecular beam epitaxy (MBE) in terms of the electronic and optical materials quality. By virtue of the quantum confinement effect,4,5 a wide range of bandgap energies and hence colors can be obtained by simply controlling the QD size (Figure 1a). At present, compositional and morphological engineering with colloidal methods extend far beyond the capacity of MBE and similar methods for a broad range of semiconductors. Owing to their low synthesis costs, along with facile solution processability, colloidal QDs have made significant commercial inroads in the lighting6 and displays markets (Figure 1b). In the realm of molecular light emitters, the synthesis toolbox of organic chemistry had been instrumental in adjusting the energy levels, such as tuning the singlet–triplet splitting,7–9 thereby boosting the development of organic LEDs (Figure 1b)10–12 for applications in lighting and TV displays. More recently, nanoscale control in materials growth has been pivotal for the generation of nonclassical light, in particular,
G. Rainò, ETH Zürich, and Empa Dübendorf, Switzerland; [email protected] H. Utzat, Stanford University, USA; [email protected] M.G. Bawendi, Massachusetts Institute of Technology, USA; [email protected] M.V. Kovalenko, ETH Zürich, and Empa Dübendorf, Switzerland; [email protected] doi:10.1557/mrs.2020.250 • VOLUME © The Author(s), 2020, published on behalf of Materials ResearchOntario, Society on by Cambridge University Presssubject to MRS 45 •ofOCTOBER 2020 • at mrs.org/bulletin Downloaded from https://www.cambridge.org/core. University of Western 11 Oct 2020 at
Data Loading...
