Effect of growth interruption on the optical properties of InAs/GaAs quantum dots

The effect of growth interruption (GI) on the optical properties of InAs/Ga As quantum dots was investigated by cw and time-resolved photoluminescence (PL). It is found that this effect depends very much on the growth conditio ns, in particular, the growth rate. In the case of low growth rate, we have found that the GI may introduce either red-shift or blue-shift in PL with increase of the interruption lime, depending on the InAs thickness. The obs erved red shift in our 1.7 monolayer (ML) sample is attributed to the evolu tion of the InAs islands during the growth interruption. While the blue-shi ft in the 3 ML sample is suggested to be mainly caused by the strain effect . In addition, nearly zero shift was observed for the sample with thickness around 2.5 ML, (C) 1999 Elsevier Science Ltd. All rights reserved.