Thermodynamics of free trions in mixed type quantum wells

Electron and Hole Trions in Wide GaAs Quantum Wells

“…Introduction The observation of charged excitons (trions) in semiconductor quantum wells (QW) by Kheng [1] has initiated experimental and theoretical work on the behaviour of electron trions (X À ) and hole trions (X ) in electric and magnetic fields [2], photoluminescence (PL) [3,4] and absorption properties [5], radiative lifetime [6], and the transition from the low-excess-density regime, where excitons and trions are clearly resolved in PL, towards the high-density regime, with a transition to the Fermi-edge singularity [7].…”

Exciton dynamics in the presence of an electron gas in GaAs quantum wells

“…Note that the intensity of the trion line is only slightly increased when the He:Ne beam injects an additional electron gas. In the present work, PL emission is always dominated by the HH-exciton and we neglect the influence of trions on the dynamics of the system [4].…”

“…The dynamics of quantum well excitons, and in particular their decay time, in the presence of an electron gas has already been studied [4], however only for high electron densities (~1 × 10 10 cm -2 ): in this regime an important fraction of the exciton population binds to electrons to form trions and the dynamics of the system is affected by the shorter trion lifetime. In this paper we report an experimental study of the effects of a low density electron gas on the exciton dynamics in a quantum well.…”

A Study of Semiconductor Quantum Structures by Microwave Modulated Photolumenescence

“…The influence of those gases are studied in mixed type I-type II quantum wells (MTQW) structure, enabling the control of the electron-density (he) between 1010_ 1011 carriers/cm2 by optical pumping [4][5][6][7].…”

“…The present study describes our attempts to follow the interactions of the 2DEG and 2DHG with other photogenerated species. The results revealed the existence of the following events: (a) attachment of an excess electron to an existing exciton in the WW, to form a negatively charged specie, named a trion [4,5]; (b) direct recombination of an ensemble of free electrons with an existing hole within the WW, forming a plasma-like emission band [5,7]; (c) indirect recombination between electron in the barrier X state and the 2DHG in the NW. The present study utilized double beam photoluminescence (PL) and microwave modulated PL (MMPL) for the study of the aforementioned processes.…”