Wavelength modification of Al<i>x</i>Ga1−<i>x</i>As quantum well heterostructure lasers by layer interdiffusion

Abstract

Data are presented showing that thermal annealing (875–-900 °C) can be used to modify the wavelength of a photopumped, low threshold AlxGa1−xAs quantum well heterostructure (QWH) laser from ∼8200 to ∼7300 Å with a threshold change from 150 to 1700 W/cm2. The energy levels of the annealed single quantum well crystal are approximated by fitting a modified Pöschl–Teller potential to the band-edge profile as modified by layer (Al–Ga) interdiffusion. The layer (Al–Ga) interdiffusion coefficient (at 875 °C) is found to be smaller, by a factor of 3–4, than previously reported. We suggest that this is due to the high quality, i.e., low defect density, of the ultralow threshold QWH crystals of this work.