Absorption and photoluminescence spectroscopy on a single self-assembled charge-tunable quantum dot
We have performed detailed photoluminescence (PL) and absorption spectroscopy on the same single self-assembled quantum dot in a charge-tunable device. The transition from neutral to charged exciton in the PL occurs at a more negative voltage than the corresponding transition in absorption. We have developed a model of the Coulomb blockade to account for this observation. At large negative bias, the absorption broadens as a result of electron and hole tunneling. We observe resonant features in this regime whenever the quantum dot hole level is resonant with two-dimensional hole states located at the capping layer-blocking barrier interface in our structure. ; We acknowledge fruitful discussions with Atac Imamoglu and financial support from DFG (SFB 631), EPSRC, DAAD and the European Union Network of Excellence SANDiE. ; Peer reviewed