Anomalous Temperature Dependence of Photoluminescence in InAs/InAlGaAs/InP Quantum Wire and Dot Hybrid Nanostructures

Self-assembled InAs quantum wires (QWRs) are fabricated on an InP substrate by solid-source molecular beam epitaxy (SSMBE). Photoluminescence (PL) spectra are investigated in these nanostructures as a function of temperature. An anomalous enhancement of PL intensity and a temperature insensitive PL emission are observed from InAs nanostructures grown on InP substrates using InAlGaAs as the matrix layer and the origin of this phenomenon is discussed. We attribute the anomalous temperature dependence of photoluminescence to the formation of Al-rich and In-rich region in the InAlGaAs buffer layer and the cap layer.