Optically pumped laser oscillation in the 1.6 - 1.8 µm region from strained layer Al0.4Ga0.6Sb/GaSb/ Al0.4Ga0.6Sb/Double heterostructures grown by molecular beam hetero-epitaxy on Si substrates

Double heterostructure lasers consisting of GaSb active layers with Al0.4Ga0.6Sb/ cladding layers were grown by molecular beam hetero-epitaxy on Si substrates. The intrinsic ∼ 12 percent lattice mismatch between the GaSb and the Si at the growth temperature is largely taken up by a GaSb/AlSb superlattice. The GaSb layer is under severe dilatory strain at room temperature due to the larger thermal contraction of the GaSb layer relative to that of Si from the growth temperature and resulting in shrinkage of the GaSb bandgap. We have observed optically pumped laser emission ranging from 1.63 μm at 85 K to 1.83 μm at 350 K. The exponential dependence of the threshold pump power and relative quantum efficiency exhibits a change in slope at ∼ 250 K. The exponential threshold-temperature dependence at 80 and 300 K are and 100 K, respectively, and are higher than previously reported for GaSb lasers. At 300 K the threshold corresponds to an equivalent current density of 12 kA/cm².