We investigate the influence of an electric field on the radiative recombination of two-dimensional electrons in the Wigner-solid regime. We find a threshold enhancement of the intensity of the luminescence accompanied by the appearance of noise, which we associate with a sliding of the pinned Wigner solid by the electric field. Our results indicate that the melting of the Wigner solid occurs in two steps and can be characterized by two critical temperatures.

The effect of carrier density, magnetic field, and final-state interactions on the radiative recombination of electrons with holes localized on acceptors in GaAs/Ga& "Al"As heterostructure is investigated. In the high-density regime, strong oscillations of the position and intensity of the emission spectrum as a function of the magnetic field are observed at even filling factors. In the low-density regime, an almost perfect cancellation of many-body effects in emission from the first subband is observed accompanied by oscillations of the emission intensity of the second subband magnetoexcitons. The peaks in the intensity of the second subband emission occur at the integer values of the ratio of the subband separation to the cyclotron energy. These results are explained by the calculated self-consistent subband structure and emission spectrum including shake-up and excitonic effects.

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