Integration of Sb-based III-V materials grown directly onto Silicon by MBE

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Modern high-performance optoelectronic devices have widely incorporated III-V semiconductor materials into their structure, especially when operating near the technologically important near-IR and mid-IR spectral ranges. These materials have attracted great interest in many sectors due to their wide range of possible bandgaps, band offsets along with high electron and hole mobilities. Properties which are useful for detectors, photovoltaics and the telecoms laser industry. With respect to lasers, the current technology has hit the limit for efficiency and bandwidth and requires a new approach for growing industrial demands.However direct integration of III-V's onto other III-V substrates such as InAs or GaSb, is not the most effective approach due to the small wafer sizes available and their high cost, bad thermal conductivity and non-optimised surface oxide layers. Integration onto Silicon on the other hand is technologically challenging, but is an important development for large-scale production and implementation of any devices. The large lattice mismatch (~13%) between for example GaSb and Silicon makes this direct epitaxial growth onto Silicon wafers difficult without techniques to manage the internal stresses inside the material in a way that protects the device to be grown on the chip. This work builds upon the pioneering work on the implementation of compound semiconductor optoelectronic devices on Silicon recently developed at Lancaster, and has resulted in one of the lowest reported threading defect densities of GaSb on Si using MBE.