Spontaneous emission study of (111) InGaAs/GaAs quantum well lasers
Spontaneous emission spectra of (111) and (100) InGaAs/GaAs QW lasers with high In content are measured up to high injection levels and compared with the theoretical results of our own model. Piezoelectric effects are investigated in (111) devices, finding significant contribution of forbidden transitions and a strong blue shift due to carrier screening of piezoelectric field. Band gap renormalization (BGR) in (111) QW lasers is estimated from the measured broadening of the low energy side of the spectrum comparing with model, and corrected by a fundamental band edge. It is also theoretically calculated, including screening effects of the coulomb interaction, in order to explain the estimated results. BGR is found to be higher in (111) samples than in (100) ones, the difference being mainly due to the hole contribution.
piezoelectric effects band gap renormalization coulomb interaction