Notes on the bunching peak of g(2) functions for correlated photons from single quantum dots

Bunching visibility for correlated photons from single GaAs quantum dots

We study photon bunching phenomena associated with biexciton-exciton cascade in single GaAs self-assembled quantum dots. Experiments carried out with a pulsed excitation source show that significant bunching is only detectable at very low excitation, where the typical intensity of photon streams is less than the half of their saturation value. Our findings are qualitatively understood with a model which accounts for Poissonian statistics in the number of excitons, predicting the height of a bunching peak being determined by the inverse of probability of finding more than one exciton.

Electron Bunching in Stacks of Coupled Quantum Dots

We study the transport properties of two double quantum dots in a parallel arrangement at temperatures of a few Kelvin. Thereby, we show that decoherence entailed by the substrate phonons affects the shot noise. For asymmetric coupling between the dots and the respective lead, the current noise is sub-Poissonian for resonant tunneling, but super-Poissonian in the vicinity of the resonances. Our results indicate that phonon emission and absorption is responsible for the shot noise enhancement. The observed asymmetry of the peaks at low temperatures stems from spontaneous emission.

Single InAsP/InP quantum dots as telecommunications-band photon sources

The optical properties of single InAsP/InP quantum dots are investigated by spectrally-resolved and time-resolved photoluminescence measurements as a function of excitation power. In the short-wavelength region (below 1.45 $μ$m), the spectra display sharp distinct peaks resulting from the discrete electron-hole states in the dots, while in the long-wavelength range (above 1.45 $μ$m), these sharp peaks lie on a broad spectral background. In both regions, cascade emission observed by time-resolved photoluminescence confirms that the quantum dots possess discrete exciton and multi-exciton states.…

Kinetic Monte Carlo simulation of shape transition in strained quantum dots

The pyramid-to-dome transition in Ge$_{x}$Si$_{1-x}$ on Si(100) initiated by step bunching on pyramidal quantum dots is atomistically simulated using a novel multi-state lattice model incorporating effective surface reconstructions. Results are explained by a simple theory based on a shallow island approximation. Under given deposition conditions in $d$ dimensions, the shape transition is shown to occur at island size $n_c$ following $n_c^{1/d} \propto x^{-ζ}$ independent of temperature and deposition rate, where $ζ\alt 2$ and $x$ is the actual Ge concentration in the island. The transition ha…

CsPbBr3量子点超晶格的室温集体闪烁与光子聚束

Room Temperature Collective Blinking and Photon Bunching from CsPbBr3 Quantum Dot Superlattice

通过自组装制备的CsPbBr3量子点超晶格在室温下表现出类似单量子点的双能级闪烁行为以及高达2.75的光子聚束度，归因于激子-双激子级联发射，为室温集体光学现象和量子光源提供了新平台。

Ultra-small (r<2 nm), stable (>1 year), mixed valence copper oxide quantum dots with anomalous band gap

Ultra-small (r<2 nm) semiconductor quantum dots (QDs) have attracted attention for applications ranging from dye sensitized solar cells to sensing due to its tunable electronic structure and band gap, and large specific surface area. However obtaining monodisperse QDs and stabilization in this size regime remains a challenge. A recent report on digestive ripening of an oxide system showed substantial promise in addressing these requirements of QDs. In this work, we report a green solution, soft chemical (chimie douce) approach for synthesis of quasi-spherical, ultra-small, stable, and monodisp…