Perspective on advances in InAsSb type II superlattices grown on virtual substrates

Metamorphic InAs1−xSbx/InAs1−ySby strained layer superlattice (SLS) structures allow for great flexibility of engineering artificial band structures and, therefore, the design of new optical and electrical properties. By using tailored virtual substrates, the average lattice constant of the SLS can be chosen anywhere between 0.606 nm (InAs) and 0.648 nm (InSb), which allows for flexibility in the choice of compositions and thicknesses of the constituent layers. These parameters can then be tuned in a wide range, which is not possible when using binary substrates. Specifically, the layer thicknesses can be nearly arbitrarily small. Short period InAs1−xSbx/InAs1−ySby SLSs exhibit strong optical absorption and improved perpendicular carrier transport and can demonstrate Dirac-type carrier dispersion, a large g-factor, and deep band inversion. The prospects for the development of devices based on these structures are discussed.