Correlation of structural and optical investigation of InGaAs/InAlAs quantum cascade laser

摘要

Double X-ray diffraction has been used to investigate InGaAs/InAlAs quantum cascade (QC) laser grown on InP substrate by molecule beam epitaxy, by means of which, excellent lattice matching, the interface smoothness, the uniformity of the thickness and the composition of the epilayer are disclosed. What is more, these results are in good agreement with designed value. The largest lattice mismatch is within 0.18% and the intersubband absorption wavelength between two quantized energy levels is achieved at about λ = 5.1μm at room temperature. At 77 K, the threshold density of the QC laser is less than 2.6 kA/cm~2 when the repetition rate is 5 kHz and the duty cycle is 1%.