Contactless Electroreflectance, Photoluminescence and Time-Resolved Photoluminescence of GaInNAs Quantum Wells Obtained by the MBE Method with N-irradiation

The optical properties of GaInNAs quantum wells (QW) grown by molecular beam epitaxywith and without N-irradiation (i.e. grown by the classical method) were investigated by thecontactless electroreflectance (CER), temperature-dependent photoluminescence (PL) andtime-resolved PL (TRPL). From CER measurements it was concluded that one type ofnitrogen nearest-neighbor environment (In-rich environment) is dominant for GaInNAs QWsgrown with N-irradiation whereas various nitrogen environments are present for the referenceGaInNAs QW (i.e. the sample obtained by the classical method). PL and TRPL measurementsclearly show that the optical properties of GaInNAs QWs are affected mainly by the amount ofthe incorporated nitride atoms. It was observed that the PL decay time decreased from ∼200to ∼40 ps when the nitrogen concentration is increased from 0.8 to 2.2%. In addition, thepresence of As flux during N-irradiation reduces the amount of the incorporated nitrogen andsimultaneously improves the optical quality of GaInNAs QWs (i.e. it weakens the carrierlocalization at low temperatures and improves the quantum efficiency of PL)