Fig. 1. AFM images (2 × 2 μm²) of lattice-matched of (a) InGaAs and (b) InAlAs in contact mode.

Fig. 2. (a) High-resolution XRD of experimental (blue, upper curve) and simulated (red, lower curve) results of lattice-matched QCL structures. (b) Partially enlarged view of satellite diffraction peaks. The full-width at half-maximum (FWHM) of satellite diffraction peaks are labelled in arcsec.

Fig. 3. (a) Power–current–voltage relations of 10 μm × 4 mm-long, and HR coated laser at different temperatures in CW condition. (b) WPE versus current injection characteristics at different temperatures

Fig. 4. Threshold current density and slope efficiency at different temperatures in pulse conditions at 1 μs, 1% duty cycle.

Fig. 5. (a) Emission spectrum at current slightly above threshold. (b) Beam picture in pulse mode at room temperature.