Shape control of InGaAs nanostructures on nominal GaAs(001): dashes and dots

A method for fabricating self-assembled InGaAs quantum dashes on a nominal GaAs(001) substrate is presented. InGaAs layers were grown on nominal GaAs(001) substrates at a low temperature to suppress the Stranski-Krastanov transition as well as indium segregation and indium desorption, then annealed at high temperatures to induce self-assembly. While typical direct growth at the annealing temperature has yielded only quantum dot shapes, our approach has enabled us to control the shape of self-assembled nanostructures from quantum dashes to quantum dots and eventually quantum dot-chains. The major factor controlling the shape of InGaAs nanostructures was found to be the thickness of the pseudomorphic In(0.4)Ga(0.6)As layer.