Fabrication of (In,Ga)As quantum-dot chains on GaAs(100)

Abstract

Nanostructure evolution during the growth of multilayers of ${\mathrm{In}}_{\text{0.5}}{\mathrm{Ga}}_{\text{0.5}}\mathrm{As/GaAs}\text{\hspace{0.17em}(100)}$ by molecular-beam epitaxy is investigated to control the formation of lines of quantum dots called quantum-dot chains. It is found that the dot chains can be substantially increased in length by the introduction of growth interruptions during the initial stages of growth of the GaAs spacer layer. Quantum-dot chains that are longer than 5 μm are obtained by adjusting the ${\mathrm{In}}_{\text{0.5}}{\mathrm{Ga}}_{\text{0.5}}\mathrm{As}$ coverage and growth interruptions. The growth procedure is also used to create a template to form InAs dots into chains with a predictable dot density. The resulting dot chains offer the possibility to engineer carrier interaction among dots for novel physical phenomena and potential devices.