Size and shape modification of self assembled InAs quantum dots and stacked layers by in-situ etching

We present investigations of the structural and optical properties of in-si tu etched, self assembled InAs islands using AsBr3 within a molecular beam epitaxy system. This procedure allows reshaping and downsizing of quantum d ots with atomic layer precision. The critical thickness of a second InAs la yer on top of a thin GaAs layer covering a first InAs dot layer was investi gated by RHEED using the 2D-3D transition due to the Stranski-Krastanov gro wth mode. In-situ etching of the GaAs spacer layer results in an array of s mall dips on the surface due to enhanced etching at locally strained areas. The dips influence the nucleation of the second dot layer. (C) 1999 Elsevi er Science Ltd. All rights reserved.