Metamorphic InAs/InGaAs quantum dots for optoelectronic devices: A review

InAs quantum dots grown on relaxed, metamorphic InGaAs buffers are an important heterostructure for the realization of devices based on GaAs substrates. In these last 20 years, thanks to the emission redshift provided by the reduction of the strain in QDs, optoelectronic devices operating in the important C-band of telecommunications at 1.55 μm have been developed. This review considers the fundamental properties of the metamorphic InAs/InGaAs quantum dot nanostructure and it presents its application for the development and fabrication of various devices. Five main instances in which metamorphic QDs have allowed to improve performances of devices are considered: i) C-band lasers, ii) C-band single photon sources, iii) multi-junction high-efficiency solar cells, iv) spectrally broadband devices, v) filtering of extended defects in lattice-mismatched systems. Through an historic presentation of main results from the literature, a complete picture of past achievements and future possible accomplishments is given, highlighting how metamorphic QDs are quite unique nanostructures, providing wider engineering possibilities for next-generation QD devices.