Low‐threshold PbEuSeTe double‐heterostructure lasers grown by molecular beam epitaxy

Lattice‐matched double‐heterostructure (DH) PbEuSeTe lasers were grown by molecular beam epitaxy (MBE) on (100) oriented PbTe substrates. Grooved mesa structures with 17–25 μm wide stripes and 0.75 μm thick Pb1−xEuxSeyTe1−y active layers with 0≤x≤0.031 were fabricated. DH diode lasers with a PbTe active layer reached a maximum cw operation temperature of 175 K which equals the highest operation temperature achieved so far by a side optical cavity (SOC) single quantum well (SQW) PbTe/PbEuSeTe laser. The threshold current density of 3.9 A/cm2 measured for this laser at 15 K is, to our knowledge, the lowest ever published for lead salt lasers. Comparison of MBE‐grown DH lasers which utilize the lattice‐matched PbTe/PbEuSeTe system to those utilizing the nonlattice‐matched PbSe/PbEuSe system shows higher operation temperatures and by far lower threshold currents for the lattice‐matched system.