Correlation between surface and buried InAs quantum dots

The optical properties of uncapped InAs∕GaAs quantum dots sitting on multiple layers of buried quantum dots are investigated through a series of samples with a different number of buried quantum dot layers. Two photoluminescence peaks are observed, one from surface quantum dots and one from buried quantum dots. Close spatial and optical correlations between surface and buried quantum dots are demonstrated. Due to the carrier transfer from buried to surface quantum dots, the photoluminescence emission from surface quantum dots is significantly improved. As a result, the surface quantum dot–buried quantum dot sample shows potential for biological sensing.