We report an infrared study of the effect of quantum well confinement on the binding energy and dynamics of shallow Be acceptors in both bulk GaAs and a series of delta-doped AlAs/GaAs multiquantum well samples with well thicknesses of 20,15 and 10nm. Low temperature far-infrared absorption measurements clearly show the three principal absorption lines due to the 1s-2p transitions of the acceptors for all four samples. The dynamics of these transitions were studied by the pump-probe technique using a free electron laser as a source of far-infrared radiation. It was found that the 2p acceptor state has a low-temperature lifetime of 360ps in the bulk, which reduces with increasing confinement, falling to 55ps in the case of the 10nm well. We suggest that the increase of phonon emission rate with decreasing well width is due to the breaking of translational symmetry in the quantum well and a subsequent increase in the single-phonon emission probability.
|Number of pages||4|
|Journal||Journal of Luminescence|
|Early online date||26 Feb 2004|
|Publication status||Published - 1 Jun 2004|
|Event||14th International Conference on Dynamical Processes in Excited States of Solids - Christchurch, New Zealand|
Duration: 3 Aug 2003 → 8 Aug 2003
Conference number: 14