Semiconductor Clusters, Nanocrystals, and Quantum Dots

  title={Semiconductor Clusters, Nanocrystals, and Quantum Dots},
  author={A. Paul Alivisatos},
  pages={933 - 937}
Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery. 
Fundamental Principles of Quantum Dots
Quantum dots are intermediates between atoms/molecules and bulk material. Therefore they can be described either by upscaling the concepts of atoms/molecules or by downscaling the concepts of bulk
Scanning Tunneling Spectroscopy of Semiconductor Quantum Dots and Nanocrystals
Quantum dots (QDs) and nanocrystals (NCs) have attracted great attention for applications in nano- and opto-electronics, quantum computation, biosensing, and nanomedicine. Three-dimensional
Single semiconductor nanocrystals: Physics and applicationsa)
Semiconductor nanocrystals are nanoscale light sources that received much attention in recent years. We will give an overview about semiconductor colloidal nanocrystals as active optical materials in
Quantum Dot Molecules and Chains
A review of results from theoretical investigations of several systems composed of two or more coupled quantum dots (known as artificial molecules or quantum dot solids) is presented. All the
Semiconducting Nanoparticles or Quantum Dots for Theranostics
Semiconductor colloidal nanocrystals are called “Quantum Dots” (QDs). QDs can be obtained when the semiconductor crystals are brought to a smaller diameter which is smaller than the Bohr exciton
Quantum Dot Photonic Crystals
An early goal of research in semiconductor quantum dots was to utilize the finite size of these materials to modify the electronic properties of the semiconductor. In particular, researchers wished
Quantum dot emitters in two-dimensional photonic crystals of macroporous silicon
We report on the incorporation of semiconductor quantum dots as internal emitters into two-dimensional photonic crystals of macroporous silicon. For this purpose we prepared composite nanotubes


Melting in Semiconductor Nanocrystals
Temperature-dependent electron diffraction studies on nanocrystals of CdS show a large depression in the melting temperature with decreasing size, as a larger fraction of the total number of atoms is on the surface.
Self-Organization of CdSe Nanocrystallites into Three-Dimensional Quantum Dot Superlattices
The self-organization of CdSe nanocrystallites into three-dimensional semiconductor quantum dot superlattices (colloidal crystals) is demonstrated. The size and spacing of the dots within the
Comparison of quantum confinement effects on the electronic absorption spectra of direct and indirect gap semiconductor nanocrystals.
The ratio of oscillator strength between direct and indirect structures does not change with size, indicating that zero-phonon transitions are not occurring in the indirect nanocrystals.
Valence-band photoemission from a quantum-dot system.
The first application of valence-band photoemission to a quantum-dot system and the spectra are qualitatively similar to those obtained for bulk cadmium sulfide, but show a shift in the valences-band maximum with size.
Preparation, characterization, and photophysics of the quantum dot quantum well system cadmium sulfide/mercury sulfide/cadmium sulfide
The synthetic procedure, the characterization, and some photophysical properties of a quantum dot quantum well (QDQW) system are described in detail. The novel structures prepared via wet chemical
Luminescence Properties of Indirect Bandgap Semiconductors: Nanocrystals of Silver Bromide
Abstract Using a modified reverse micelle protocol with acetyl bromide as the bromide source, AgBr nanocrystals can be grown over a size range from 30 A radius to bulk. These clusters exhibit quantum
Theory of the linear and nonlinear optical properties of semiconductor microcrystallites.
In the limit of a QD much smaller than the bulk exciton size, the linear spectrum will be a series of lines, and the phonon broadening of these lines is considered.
Electronic spectroscopy and photophysics of Si nanocrystals. Relationship to bulk c-Si and porous Si
The structural characterization, electronic spectroscopy, and excited-state dynamics of surface-oxidized Si nanocrystals, prepared in a high-temperature aerosol apparatus, are studied to gain insight
Single-electron charging in double and triple quantum dots with tunable coupling.
We report low-temperature tunneling measurements at zero magnetic field through double and triple quantum dots with adjustable interdot coupling, fabricated in a GaAs/AlGaAs heterostructure. As the
Electronic states of semiconductor clusters: Homogeneous and inhomogeneous broadening of the optical spectrum
The homogeneous (single‐cluster) and inhomogeneous contributions to the low temperature electronic absorption spectrum of 35–50 A diameter CdSe clusters are separated using transient photophysical