Observation of compressive and tensile strains in InGaAs/GaAs by photoluminescence spectroscopy

Abstract

Variation in the magnitude and sign of the strain in GaAs/InGaAs/GaAs single quantum wells are studied as a function of layer thickness using photoluminescence spectroscopy. It is found that as the compressively strained ternary layer relaxes with increasing thickness, a tensile strain is introduced in the GaAs capping layer. This reduces the GaAs band gap and lifts the degeneracy of the valence band, which becomes light hole in character.