Modeling carrier transport in mid-infrared VCSELs with type-II superlattices and tunnel junctions

Vertical-cavity surface-emitting lasers are promising light sources for sensing and spectroscopy applications in the midinfrared 3 ÷ 4 μm spectral region. A type-II superlattice active region is used for carrier injection and confinement, while a buried tunnel junction defines a current aperture, decreasing the series resistivity. Highly nanostructured to optimize device performance, mid-infrared VCSELs pose modeling challenges beyond semiclassical approaches. We propose a quantum-corrected semiclassical approach to device design and optimization, complementing a drift-diffusion solver with a nonequilibrium Green’s function description of band-to-band tunneling in the buried tunnel junction, and a local density of states computed from the solution of the Schrödinger equation in the superlattice active region.