Emission energy tuning of InAs-quantum dots for fabrication of broadband superluminescent diodes

Multiple layers of InAs quantum dots (QDs) where the dots height was tuned from one layer to another have been grown and characterized. The desired dots height within one layer was controlled by the thickness of the GaAs cap layer grown at low temperature (@510°C) before annealing the dots to 610°C. Four combined layers of QDs where the thickness of the cap layer was varied from 2.8 nm to 6.5 nm resulted in a photoluminescence spectrum with full width at half maximum of 125 nm at peak wavelength energy of 1.06 ¿m. Overlapping several layers of QDs of different heights is a reliable and predictable approach that can be used to engineer the bandwidth emission spectrum for fabrication of 1 ¿m broadband superluminescent diodes. 3 dB and 10 dB bandwidth of 100 nm and 230 nm were obtained under 200 mA injection current in CW operation mode at 55 K, respectively.