Tuning InAs/GaAs quantum dot properties under Stranski-Krastanov growth mode for 1.3 µm applications

The authors present a systematic study of the effect of growth parameters on the structural and optical properties of InAs quantum dot (QD) grown under Stranski-Krastanov mode by MBE. The dot d. is significantly reduced 1.9 * 1010-0.6 * 1010 cm-2 as the growth rate decreases from 0.075 to 0.019 ML/s, while the island size becomes larger. Correspondingly, the emission wavelength shifts to the longer side. By increasing the In fraction in the InGaAs capping layer, the emission wavelength increases further. At In fraction of 0.3, a ground state transition wavelength as long as 1.4 micro m with the excited state transition wavelength of .apprx.1.3 micro m was achieved in the authors' dots. The optical properties of QDs with a ground state transition wavelength of 1.3 micro m but with different growth techniques were compared. The QDs grown with higher rate and embedded by InGaAs have a higher intensity satn. level from excitation dependent photoluminescence measurements and a smaller intensity decrease from temp. dependent measurements. Finally, single mirror light emitting diodes with a QD embedded in InGaAs were fabricated. The quantum efficiency at room temp. is 1.3%, corresponding to a radiative efficiency of 21.5%. [on SciFinder (R)]