Carrier dynamics in Ga(NAsP)/Si multi-quantum well heterostructures with varying well thickness

•Time-resolved photoluminescence measurements in Ga(NAsP)/(BGa)(AsP)/Si MQWHs.•The impact of the QW thickness on the optical properties and carrier dynamics.•A shortening in the PL decay time with increasing QW thickness.•An increasing number of defects in the QW material for broader QWs.•A strong dependence of the PL decay time on the emission energy at low temperatures.

Time-resolved photoluminescence (TR-PL) measurements have been performed in Ga(NAsP)/(BGa)(AsP) multi-quantum well heterostructures (MQWHs) with different well thicknesses. The studied structures have been pseudomorphically grown on Si substrates by metal organic vapor phase epitaxy (MOVPE) with an N content of about 7%. Experimental results reveal a shortening in the PL decay time with increasing QW thickness, meanwhile, accompanied by a decrease in the PL intensity. We attribute this behavior to an increasing non-radiative recombination rate for broader QWs which arises from an increasing number of defects in the QW material. The emission-energy distribution of the PL decay time is studied at various temperatures. The PL decay time strongly depends on the emission energy at low temperatures and becomes emission-energy-independent close to room temperature. This is discussed in terms of the carrier localization in the studied structures.