Radiation emitted by quantum-well InGaAs structures I. Spontaneous emission spectra

The spontaneous emission spectra of strained InGaAs quantum wells in the spectral range 1.2-1.5 eV were studied experimentally at 4.2-286 K with pump currents up to similar to 9.2 kA.cm(-2). An interpretation of the observed bands is given. The transition 1e-1hh (TE polarization) dominates the spectrum. The position of the peak for this transition is virtually current-independent. No indications of a "red" shift, expected at a high carrier density, were observed. The weak forbidden transitions (1e-2hh) were identified. The long-wavelength edge of the band drops off exponentially, by analogy with the well-known Urbach rule for the absorption edge. (C) 1998 American Institute of Physics.