Optical characterization of InGaAs/GaAs quantum dots defined by lateral top barrier modulation

Abstract

We have produced effectively buried quantum well dots on the basis of InGaAs/GaAs single quantum wells using high resolution electron beam lithography and selective wet etching of the top barrier. The lateral barriers are realized by the difference in quantization energy in quantum wells with a semiconductor top barrier compared to quantum wells with a vacuum potential barrier. Dot structures with widths down to 20 nm have been generated. We observe that the structures maintain high luminescence efficiencies down to the smallest sizes. We also observe a blueshift of up to 9 meV for 23 nm quantum dots. High excitation photoluminescence shows a second lateral subband in small dot structures.