The negatively charged exciton, X-, is a bound state of two electrons and a hole. It appears in the photoluminescence spectrum of GaAs quantum wells with low electron density as a narrow line ~ 1 meV below the neutral exciton line. This energy is the binding energy of an extra electron to an exciton. We have conducted intensive experimental studies of its energy spectrum, dynamics and structure. A special effort was devoted to understanding its behavior in strong magnetic fields, when the cyclotron diameter becomes smaller than the Bohr diameter, and the internal structure is expected to be modified.
The X- is the semiconductor analogue of the hydrogen ion, H-. Another bound state that is observed in quantum wells with a low density of holes is the positively charged exciton, X+. It consists of two holes and an electron, and is a semiconductor analogue of the hydrogen molecule ion H2+. These two charged-excitons are the ground state of the Ne+h or Nh+e system.
- 1. G. Finkelstein, H. Shtrikman and I. Bar-Joseph
Negatively
and positively charged excitons in GaAs/AlGaAs quantum wells.
Phys. Rev. B 53, R1709 (1996).
- 2. G. Finkelstein, H. Shtrikman and I. Bar-Joseph
Shakeup
processes in the recombination spectra of negatively charged excitons.
Phys. Rev. B 53, 12593 (1996).
- 3. G. Finkelstein, H. Shtrikman and I. Bar-Joseph
Optical
spectroscopy of neutral and charged excitons in GaAs/AlGaAs quantum
wells in high magnetic fields
Surf. Science 361/362, 357 (1996).
- 4. G. Finkelstein, V. Umansky, I. Bar-Joseph, V. Ciulin,
S. Haacke, J-D Ganiere and B. Deveaud
Charged
exciton dynamics in GaAs quantum wells.
Phys. Rev. B, 58 12637, 1998.
- 5. V. Ciulin, G. Finkelstein, S. Haacke, J-D Ganiere, V.
Umansky, I. Bar-Joseph, and B. Deveaud .
Dynamics
of charged excitons in GaAs quantum wells under high magnetic
field.
Physica B 258, 466 (1998).
- 6. S.Glasberg, G.Finkelstein, H.Shtrikman, and I.Bar-Joseph
Comparative
study of the negatively and positively charged excitons in GaAs
quantum wells.
Phys. Rev. B. 59, 10425, (1999).
- 7. G.Yusa, H.Shtrikman, and I.Bar-Joseph
The
onset of exciton absorption in modulation doped GaAs quantum wells
Phys. Rev. B 62, 15390 (2000).
- 8. G.Yusa, H.Shtrikman, and I.Bar-Joseph
Charged-excitons
in the fractional quantum Hall regime
Submitted, Cond-Mat 0103561 (2001).
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