BRIEF COMMUNICATIONS: Optically pumped Pb1-xSnxSe1-yTey heterojunction lasers with matched gratings at the interface
An investigation was made of the photoluminescence emitted from epitaxial films of Pb1–xSnxSe1–yTey solid solutions (0 ≤ x 0.47, 0 ≤ y 0.65), grown by the method of liquid epitaxy on n-type PbSe substrates. Next, n-Pb1–xSnxSe1–yTey/n-PbSe heterostructures, with the Pb1–xSnxSe1–yTey active layer (0.015 ≤ x ≤ 0.092, 0.0006 ≤ y ≤ 0.026), were matched in respect of the lattice constant to the substrate (Δa/a =10−1–10−3%) and used as optically excited heterolasers. The spectral and threshold characteristics were determined as a function of the thickness of the active layer d, temperature, and resonator length. Variation of the composition of the active layer altered the emission wavelength within the range 8–12.5 μ at 77°K. Electron and optical confinement effects were observed when the thickness d was reduced. For the optimal thickness dopt≈/cm2 at 77°K. The loss factor (5.5 cm−1), gain (0.11 cm/W), and carrier density (2×1017 cm−3) in the active layer were determined.