Emission from quantum-well InGaAs structures

An experimental investigation was made of the spontaneous emission spectra of InGaAs laser structures based on strained quantum wells. The density of the injec- tion current was up to ~9.2 kA cm ^–2 and the investigation was carried out in the temperature range 4.2 — 286 K. The energy of the emitted photons was 1.2 — 1.5 eV. The spectrum was dominated by the 1e — 1hh transition and the peak representing this transition was practically independent of the current. There was no evidence of the ‘red’ shift predicted by the many-body theory for high carrier concentrations. Weak forbidden transitions (1e — 2hh, etc.) were identified. The long-wavelength edge of the emission band varied exponentially in accordance with the familiar Urbach rule for the absorption edge.