Optical properties and structure of InAs quantum dots in near-infrared band

Abstract

The InAs quantum dots (QDs) grown by molecular beam epitaxy (MBE) are studied as a function of growth temperature at a specific InAs coverage of 2.7 ML. The QDs density is significantly reduced from 8.0 × 10¹⁰ to 5.0 × 10⁹ cm^-2 as the growth temperature increases from 480°C to 520°C, while the average QDs diameter and height becomes larger. The effects of the growth temperature on the evolution of bimodal QDs are investigated by combining atomic force microscopy (AFM) and photoluminescence (PL). Results show that the formation of the bimodal QDs depends on the growth temperature: at a growth temperature of 480°C, large QDs result from the small QDs coalition; at a growth temperature of 535°C, the indium desorption and InAs segregation result in the formation of small QDs.

Keywords

quantum dot (QD) / molecular beam epitaxy (MBE) / atomic force microscopy (AFM) / photoluminescence (PL)