Topic
Photoluminescence
About: Photoluminescence is a research topic. Over the lifetime, 83414 publications have been published within this topic receiving 1850414 citations.
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TL;DR: The observation of strong coupling of a single two-level solid-state system with a photon, as realized by a single quantum dot in a semiconductor microcavity, may provide a basis for future applications in quantum information processing or schemes for coherent control.
Abstract: Cavity quantum electrodynamics, a central research field in optics and solid-state physics, addresses properties of atom-like emitters in cavities and can be divided into a weak and a strong coupling regime. For weak coupling, the spontaneous emission can be enhanced or reduced compared with its vacuum level by tuning discrete cavity modes in and out of resonance with the emitter. However, the most striking change of emission properties occurs when the conditions for strong coupling are fulfilled. In this case there is a change from the usual irreversible spontaneous emission to a reversible exchange of energy between the emitter and the cavity mode. This coherent coupling may provide a basis for future applications in quantum information processing or schemes for coherent control. Until now, strong coupling of individual two-level systems has been observed only for atoms in large cavities. Here we report the observation of strong coupling of a single two-level solid-state system with a photon, as realized by a single quantum dot in a semiconductor microcavity. The strong coupling is manifest in photoluminescence data that display anti-crossings between the quantum dot exciton and cavity-mode dispersion relations, characterized by a vacuum Rabi splitting of about 140 microeV.
1,809 citations
TL;DR: The fundamental photoluminescence properties of individual, isolated indium phosphide nanowires were characterized to define their potential for optoelectronics and create polarization-sensitive nanoscale photodetectors that may prove useful in integrated photonic circuits, optical switches and interconnects, near-field imaging, and high-resolution detectors.
Abstract: We have characterized the fundamental photoluminescence (PL) properties of individual, isolated indium phosphide (InP) nanowires to define their potential for optoelectronics. Polarization-sensitive measurements reveal a striking anisotropy in the PL intensity recorded parallel and perpendicular to the long axis of a nanowire. The order-of-magnitude polarization anisotropy was quantitatively explained in terms of the large dielectric contrast between these free-standing nanowires and surrounding environment, as opposed to quantum confinement effects. This intrinsic anisotropy was used to create polarization-sensitive nanoscale photodetectors that may prove useful in integrated photonic circuits, optical switches and interconnects, near-field imaging, and high-resolution detectors.
1,798 citations
TL;DR: The photoluminescence (PL) of silicon quantum dots present in porous silicon can be tuned from the near infrared to the ultraviolet when the surface is passivated with Si-H bonds as discussed by the authors.
Abstract: Depending on the size, the photoluminescence (PL) of silicon quantum dots present in porous silicon can be tuned from the near infrared to the ultraviolet when the surface is passivated with Si-H bonds. After exposure to oxygen, the PL shifts to the red by as much as 1 eV. This shift and the changes in PL intensity and decay time, show that both quantum confinement and surface passivation determine the electronic states of silicon quantum dots. A theoretical model in which new electronic states appear in the band gap of the smaller quantum dots when a Si-O bond is formed, is in good agreement with experiments. This result clarifies the controversy regarding the PL mechanisms in porous silicon.
1,793 citations
TL;DR: A ligand-assisted reprecipitation strategy is developed to fabricate brightly luminescent and color-tunable colloidal CH3NH3PbX3 quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies, expected to exhibit interesting nanoscale excitonic properties.
Abstract: Organometal halide perovskites are inexpensive materials with desirable characteristics of color-tunable and narrow-band emissions for lighting and display technology, but they suffer from low photoluminescence quantum yields at low excitation fluencies. Here we developed a ligand-assisted reprecipitation strategy to fabricate brightly luminescent and color-tunable colloidal CH3NH3PbX3 (X = Br, I, Cl) quantum dots with absolute quantum yield up to 70% at room temperature and low excitation fluencies. To illustrate the photoluminescence enhancements in these quantum dots, we conducted comprehensive composition and surface characterizations and determined the time- and temperature-dependent photoluminescence spectra. Comparisons between small-sized CH3NH3PbBr3 quantum dots (average diameter 3.3 nm) and corresponding micrometer-sized bulk particles (2–8 μm) suggest that the intense increased photoluminescence quantum yield originates from the increase of exciton binding energy due to size reduction as well a...
1,756 citations
TL;DR: A review of current research on the optical properties of ZnO nanostructures and results of nonlinear optical studies, such as second-harmonic generation, are presented.
Abstract: We present a review of current research on the optical properties of ZnO nanostructures. We provide a brief introduction to different fabrication methods for various ZnO nanostructures and some general guidelines on how fabrication parameters (temperature, vapor-phase versus solution-phase deposition, etc.) affect their properties. A detailed discussion of photoluminescence, both in the UV region and in the visible spectral range, is provided. In addition, different gain (excitonic versus electron hole plasma) and feedback (random lasing versus individual nanostructures functioning as Fabry-Perot resonators) mechanisms for achieving stimulated emission are described. The factors affecting the achievement of stimulated emission are discussed, and the results of time-resolved studies of stimulated emission are summarized. Then, results of nonlinear optical studies, such as second-harmonic generation, are presented. Optical properties of doped ZnO nanostructures are also discussed, along with a concluding outlook for research into the optical properties of ZnO.
1,746 citations