Indirect Excitonic lifetimes
In a Quantum Dot Molecule, electrons and holes can be spatially distributed into two separate quantum dots. This “indirect ” exciton has a recombination energy that depends strongly on applied electric field and an optical dipole that is significantly reduced because of the reduced overlap of electron and hole wavefunctions. This reduced overlap should lead to changes in the excitonic lifetime, which is typically on the order of 1 ns for a “direct” exciton. Longer excitonic lifetimes could result in longer carrier or spin storage times. Control of exciton lifetimes is also critical to the design and performance of intermediate band solar cells. In this project we study the lifetimes of indirect excitons using time-correlated single photon counting.
M. Scheibner, M.F. Doty, I.V. Ponomarev, A.S. Bracker, E.A. Stinaff, V.L. Korenev, T.L. Reinecke, D. Gammon. Spin Fine-Structure in Optically Excited Quantum Dot Molecules. Phys. Rev. B 75, 245318 (2007)
A.S. Bracker, M. Scheibner, M.F. Doty, E.A. Stinaff, I.V. Ponomarev, J.C. Kim, L.J. Whitman, T.L. Reinecke, D. Gammon. Engineering electron and hole tunneling with asymmetric InAs quantum dot molecules. Appl. Phys. Lett. 89, 233110 (2006)
E.A. Stinaff, M. Scheibner, A.S. Bracker, I.V. Ponomarev, V.L. Korenev, M.E. Ware, M.F. Doty, T.L. Reinecke, D. Gammon. Optical signatures of coupled quantum dots. Science 311 636 (2006)