Formation of vertically aligned arrays of strained InAs quantum dots in a GaAs(100) matrix

A method of controlling the shape and size of elastically stressed InAs islands grown in a GaAs matrix is proposed and realized. The method is based on vertical alignment of the islands in the neighboring rows, an effect observed when several rows of islands are separated by spacers whose thickness does not exceed the characteristic island height. As a result of the vertical alignment, nonpyramidal quantum dots with an increased height-to-base ratio (confirmed by transmission electron microscopy) are formed. The results of optical investigations of such structures show large changes in the carrier energy spectrum in the InAs quantum islands. (C) 1996 American Institute of Physics.