Carriers’ localization and thermal redistribution in InAlAs/InP grown by MOCVD on (311)A- and (311)B-InP substrates
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We present a photoluminescence (PL) study of the optical properties in In0.513Al0.487As/InP heterostructures grown on (311)A- and (311)B-InP substrates. The exciton localization effect is studied by considering the substrate polarity. An asymmetric PL line shape denoted P1 and P1′ associated with the type II transition, for the (311)B and (311)A substrate polarity, respectively, in the lower energies side has been found in both samples. Using PL technique, luminescence measurements were carried out as a function of temperature in the range of [10–300 K]. The PL peak energy, the PL intensity and the full width at half maximum (FWHM) display anomalous behaviors such as S-shaped and N-shaped. Implying the presence of localized carriers, they were ascribed to the energy potential modulation associated to the Indium cluster formation and piezoelectric (PZ) field. We investigate the presence of localized carriers by excitation density variation. With the assistance of localized-state ensemble (LSE) luminescence model, the PL spectra of the samples are quantitatively explained into the entire temperature range.
This work was supported by the Université de Monastir, Laboratoire de Micro-Opto électronique et Nanostructures (LMON), Faculté des Sciences, 5019, Monastir, Tunisia.