Journal of Alloys and Compounds | 2019
Achieving wavelength emission beyond the C-band from Type-II InAs-GaAsSb quantum dots grown monolithically on silicon substrate
Abstract
Abstract The optical quality enhancement of a GaAs template grown on Silicon substrate using InGaAs/GaAs Dislocation Filters (DFs) combined with an annealing step have been assessed optically using Photoluminescence (PL) of embedded InAs/InGaAs QDs within a GaAs matrix. An annealing temperature after the growth of the DFs of 690\u202f°C was shown to be optimum, giving an enhanced PL emission from the embedded InAs QDs in terms of intensity and Full Width at Half Maximum (FWHM). InAs quantum dots capped with GaAsSb grown at different temperatures were grown on the optimized GaAs template on Si. The prepared samples were characterized by PL, Atomic Force Microscopy (AFM), excitation power and dependent PL at 77\u202fK and 300\u202fK. At 77\u202fK, the InAs/GaAsSb grown at 484\u202f°C showed a type II band alignment with an emission wavelength of 1297\u202fnm, which is shorter than the emission obtained from the reference sample, where the GaAsSb-capped dots were grown on GaAs (1357\u202fnm). By reducing the GaAsSb capping layer growth temperatures to 465\u202f°C and 450\u202f°C, the wavelength at 77\u202fK was extended to 1375\u202fnm and 1480\u202fnm respectively, resulting from an increased Sb content in the capping layer. At 300\u202fK, a long wavelength emission of 1623\u202fnm have been achieved.