2008/02/25 by Paul A. Dalgarno, P. A. Dalgarno, Jason M. Smith +11 · 2 citations
Materials Science · Physics and Astronomy · #Atomic physics #Biexciton #Charge (physics) #Condensed matter physics #Coulomb #Electric field #Electron #Exciton #Physics #Quantum Dots Synthesis And Properties #Quantum and electron transport phenomena #Quantum dot #Quantum mechanics #Semiconductor Quantum Structures and Devices #Spontaneous emission #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.77.245311
8 pages, 7 figures, submitted to Phys. Rev. B
arxiv created 2008/02/25 · openalex publication_date 2008/06/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present results on the charge dependence of the radiative recombination lifetime, \ensuremathτ, and the emission energy of excitons confined to single self-assembled InGaAs quantum dots. There are significant dot-to-dot fluctuations in the lifetimes for a particular emission energy. To reach general conclusions, we present the statistical behavior by analyzing data recorded on a large number of individual quantum dots. Exciton charge is controlled with extremely high fidelity through an n-type field effect structure, which provides access to the neutral exciton (X0), the biexciton (2X0), and the positively (X1+) and negatively (X^1\ensuremath-) charged excitons. We find significant differences in the recombination lifetime of each exciton such that, on average, \ensuremathτ(X^1\ensuremath-)/\ensuremathτ(X0)=1.25, \ensuremathτ(X1+)/\ensuremathτ(X0)=1.58, and \ensuremathτ(2X0)/\ensuremathτ(X0)=0.65. We attribute the change in lifetime to significant changes in the single particle hole wave function on charging the dot, an effect more pronounced on charging X0 with a single hole than with a single electron. We verify this interpretation by recasting the experimental data on exciton energies in terms of Coulomb energies. We directly show that the electron-hole Coulomb energy is charge dependent, reducing in value by 5%--10% in the presence of an additional electron, and that the electron-electron and hole-hole Coulomb energies are almost equal.