InSb-based quantum dot nanostructures for mid-infrared photonic devices

Abstract

Novel InSb quantum dot (QD) nanostructures grown by molecular beam epitaxy (MBE) are investigated in order to improve the performance of light sources and detectors for the technologically important mid-infrared (2-5 µm) spectral range. Unlike the InAs/GaAs system which has a similar lattice mismatch, the growth of InSb/InAs QDs by MBE is a challenging task due to Sb segregation and surfactant effects. These problems can be overcome by using an Sb-As exchange growth technique to realize uniform, dense arrays (dot density ~10 12 cm-2) of extremely small (mean diameter ~2.5 nm) InSb submonolayer QDs in InAs. Light emitting diodes (LEDs) containing ten layers of InSb QDs exhibit bright electroluminescence peaking at 3.8 µm at room temperature. These devices show superior temperature quenching compared with bulk and quantum well (QW) LEDs due to a reduction in Auger recombination. We also report the growth of InSb QDs in InAs/AlAsSb 'W' QWs grown on GaSb substrates which are designed to increase the electron-hole (e-h) wavefunction overlap to ~75%. These samples exhibit very good structural quality and photoluminescence peaking near 3.0 μm at low temperatures.

Self-Catalyzed InSb/InAs Quantum Dot Nanowires

“…Moreover, InAs x Sb 1–x alloys provide the narrowest tunable bandgap for the infrared spectrum range, broadening the possible applications for devices operating in the mid and long wavelength infrared in emission or detection, especially for environmental gas detectors and security applications [ 25 , 28 , 29 , 30 ]. Since the last decade, much effort has been put into the growth of self-assembled InSb and InAsSb QDs [ 20 , 31 , 32 , 33 , 34 , 35 , 36 ]. However, the direct growth of InSb and InAsSb QDs of high crystal quality on commonly available semiconductor substrates is very challenging owing to the large lattice mismatch and to Sb segregation and surfactant effect [ 33 , 34 ].…”

“…Since the last decade, much effort has been put into the growth of self-assembled InSb and InAsSb QDs [ 20 , 31 , 32 , 33 , 34 , 35 , 36 ]. However, the direct growth of InSb and InAsSb QDs of high crystal quality on commonly available semiconductor substrates is very challenging owing to the large lattice mismatch and to Sb segregation and surfactant effect [ 33 , 34 ]. Different approaches have been proposed for different types of substrate by introducing an intermediate layer of other materials in order to reduce the lattice mismatch [ 31 , 33 ] leading to very difficult growth protocols [ 20 , 31 , 33 ].…”

“…However, the direct growth of InSb and InAsSb QDs of high crystal quality on commonly available semiconductor substrates is very challenging owing to the large lattice mismatch and to Sb segregation and surfactant effect [ 33 , 34 ]. Different approaches have been proposed for different types of substrate by introducing an intermediate layer of other materials in order to reduce the lattice mismatch [ 31 , 33 ] leading to very difficult growth protocols [ 20 , 31 , 33 ]. The NW geometry offers a great platform for improving the InAs/InSb material system quality and range of possible applications.…”