Luminescence properties of (GaAs)l(AlAs)m superlattices with (l,m) ranging from 1 to 73

Abstract
We present a systematic investigation of (GaAs)l(AlAs)m (lm) superlattices by photoluminescence excitation at T=2 K in the energy range of 1.52–2.42 eV. The luminescence spectra of the superlattice samples differ strongly from the spectra of the ternary Al0.5Ga0.5As alloy. The luminescence peak energy is largest for l,m=3 and decreases when l,ml,m≤15 show sidebands of low intensity. The excitation spectra for superlattices with l,m≤8 show threshold energies but no discrete states corresponding to light‐hole related transitions. Superlattices with l,m>15 display a splitting of light‐ and heavy‐hole states. The optical measurements confirm that this new material has properties which are very different from the ternary Al0.5Ga0.5As alloy.