Emission from Mesoscopic-Size Islands Formed in a GaAs/AlAs Double Layer Structure

A. Wysmołek, B. Chwalisz, M. Potemski, R. Stępniewski, A. Babiński, S. Raymond, V. Thierry-Mieg
2004 Acta Physica Polonica. A  
The nature of sharp emission lines which are present in macro--luminescence experiments on a type-II GaAs/AlAs double quantum well structure is discussed. The experiments, which also include micro-luminescence measurements, allowed us to conclude that the sharp emission lines observed originate from lateral GaAlAs islands of a few µm in diameter. They serve as efficient type-I recombination centers for indirect excitons and/or carriers which diffuse in the GaAs/AlAs QW structure and strongly
more » ... ure and strongly affect the emission processes observed in macro-luminescence experiments. These traps can easily be filled with electron-hole pairs, giving rise to the formation of neutral excitons as well as more complex excitonic molecules. Magnetoluminescence spectra from single islands resemble those observed for natural quantum dots formed in narrow GaAs quantum wells.
doi:10.12693/aphyspola.106.367 fatcat:orz2eaushrdt7hdlbwg6mw43gq