Self-Assembled Unstrained InGaAs Quantum Dashes

We describe a technique for MBE-based fabrication of unstrained quantum dashes with Al$_{x}$In$_{y}$Ga$_{1-x-y}$As alloys lattice-matched to InP substrates. Templates for lattice-matched quantum dash growth are obtained by combining molecular beam epitaxy with \textit{in situ} etching by arsenic bromide. A seed layer of self-assembled InAs quantum dashes is converted into nanotrench templates through overgrowth followed by strain-enhanced etching. We have explored limitations on the accessible range of alloy compositions imposed by the etch process and found that strain-induced etching is limited to compounds with low Al content. Nanotrench templates can be filled with lattice-matched alloys of varied compositions to define barriers and quantum wires that could lead to optoelectronic devices in a spectral range around 1.5 $\mu$m. Here we also present Atomic Force Microscopy and Photoluminescence data obtained from self assembled unstrained In$_{0.53}$Ga$_{0.47}$As Quantum Dashes.