Using the tensile stress field to control quantum dot arrangements

In this paper, a tensile-strained layer is used to control the quantum dot arrangements. A 3 nn GaAs tensile-strained layer is grown on InP (001) subs trate, and a four-monolayer InAs compressed layer is then grown on top by L P-MOVPE. Atomic force microscopy (AFM) measurements were performed. AFM ima ges indicate that the InAs quantum dots are arranged along two orthogonal d irections, their diameter is about 30 nm, the size fluctuation is only 10%, and their density is 8.8 x 10(9) cm(-2), which is higher than that grown d irectly on InP or GaAs substrates. An identical structure, except for the p resence of 30 nm of GaAs, was also grown. The islands on top of the 30 nm G aAs are mainly very big and rectangular in shape. We demonstrate that these characteristics originate from the modulated stress held of the GaAs tensi le-strained layer. (C) 1999 Elsevier Science B.V. All rights reserved.