Growth and characterization of ultrathin InAs/GaAs quantum wells

Abstract

We report on the MBE growth of nominally 2 and 3 monolayers (ML) thick InAs quantum wells embedded in GaAs. The structures presented were grown using different substrate temperatures and growth interruption times. They were characterized by high resolution x-ray diffraction and low temperature photoluminescence (PL) measurements. The PL spectrum for the 3 ML sample was dominated by a strong electron-hole pair recombination at 1.262 eV, with a full width at half maximum (FWHM) of 39 meV. For a nominally 2 ML InAs quantum well the main PL peak was shifted to higher energies. The PL emission from a second 2 ML thick film having a growth interruption at the InAs/GaAs interface exhibited a large shift to lower energies and a broader linewidth. The evolution from 2 to 3 dimensional growth mode is reflected in the PL spectra and the x-ray diffraction patterns. The spectral positions of the PL peaks are in good agreement with estimates of the subband energies from a 3-band Kane model including the effects of strain.