Group-III assisted catalyst-free growth of InGaAs nanowires and the formation of quantum dots

Abstract

Growth of GaAs and InGaAs nanowires by the group-III assisted Molecular Beam Epitaxy growth method is studied in dependence of growth temperature, with the objective of maximizing the indium incorporation. Nanowire growth was achieved for growth temperatures as low as 550{\deg}C. The incorporation of indium was studied by low temperature micro-photoluminescence spectroscopy, Raman spectroscopy and electron energy loss spectroscopy. The results show that the incorporation of indium lowering the growth temperature does not have an effect in increasing the indium concentration in the bulk of the nanowire, which is limited to 3-5%. For growth temperatures below 575{\deg}C, indium rich regions form at the surface of the nanowires as a consequence of the radial growth. This results in the formation of quantum dots, which exhibit extremely sharp luminescence.