A theoretical study of InAs/InP and InAs/GaAs QDs systems: Formation mechanisms and photoluminescence characterization

Abstract

In this work, we have studied structural, electronic and optical properties of InAs/InP quantum dots (QDs). Our results were compared with the theoretical and experimental results reported in the literature and with those of QDs InAs/GaAs which is the most studied system. We have shown that, even though InAs/InP and InAs/GaAs QDs have the same dot (InAs), their electronic, optical and structural properties differ considerably.The main shared characteristics and dissimilarities between the InAs/InP and the InAs/GaAs QDs systems have been pointed out. It has been shown that these dissimilarities have a significant impact on their applications. Our photoluminescence (PL) characterization simulation model, presented in a previous work, was used. For InAs/InP QDs system, two cases were considered: the strong quantum confinement regime and the weak one. For each regime, two hypotheses were analysed, one with non-radiative recombination centers and another without. It was highlighted a shift of the PL peaks and a broadening of the spectra with the increase of the QDs size for both systems. But, for InAs/InP QDs system the broadening of the spectra is less strong. This is attributed to the lattice mismatch which is smaller for InAs/InP compared with InAs/GaAs. It has been shown that InAs/InP QDs are less suitable for applications in solar cells, due to the short lifetime of the charge carriers. On the other hand, InAs/GaAs QDs are not able to reach the 1.5 µm wavelength for telecom applications, also called C-band telecom, because they strongly degrade for emission wavelengths larger than 1.3 µm.