Controlled fabrication of InGaAs quantum dots by selective area epitaxy MOCVD growth

Control over the location, distribution, and size of quantum dots is essential for the engineering of next-generation semiconductor devices employing these remarkable nanostructures. We describe two approaches for achieving some level of this control in the InGaAs/GaAs material system. The first allows a degree of spatial selectivity by using strain differences in patterned InGaAs thin films as preferential sites for quantum dot growth. This method results in patterns of dots similar to those grown by self-assembly on an unpatterned InGaAs layer. The second method employs more conventional selective area epitaxy using a thin silicon dioxide mask patterned by electron beam lithography. This method allows control over the location of each quantum dot and variation of dot size through manipulation of the mask pattern. We present data on arrays of highly uniform InGaAs quantum dots fabricated in this manner.