Balancing the Number of Quantum Wells in HgCdTe/CdHgTe Heterostructures for Mid-Infrared Lasing

Abstract

HgCdTe-based heterostructures with quantum wells (QWs) are a promising material for semiconductor lasers in the atmospheric transparency window (3–5 μm) thanks to the possibility of suppressing Auger recombination due to the no-parabolic law of carrier dispersion. In this work, we analyze the thresholds of stimulated emission (SE) under optical pumping from heterostructures with a different number of QWs in the active region of the structure. Total losses in structures are determined from the comparison of thresholds for the different number of QWs in the active region. It is shown that, thanks to the increased modal gain, a higher number of QWs results in lower threshold pumping intensity and, consequently, higher temperature of SE. These results indicate that improvements to the modal gain can result in a moderate uplift in the temperature of SE from mid-infrared HgCdTe-based heterostructures. On the other hand, at a high enough QW count threshold, the intensity no longer depends on the number of the QWs and is determined by the transparency concentration of a single QW.

Photoluminescence in Mercury Cadmium Telluride – a Historical Retrospective. Part II: 2004–2022

“…The work soon turned into an extended study of stimulated emission from the QW heterostructures, and later, from bespoke MCTbased laser structures designed for both long-and middle IR ranges (for the latest results on the topic at the time of writing of this review, see, e.g., Refs. [63,64]). In the meantime, a study of interband PL from epitaxial films at wavelengths up to 26 µm was performed [65].…”

“…The subject of the investigation was now heteroepitaxial films grown on (013)GaAs or (013)Si substrates using the same MBE technology as in Refs. [55][56][57][58][59][60][61][62][63][64][65][66][67][68]. PL was studied in the temperature range 4.2 K < T < 300 K under pulsed excitation with a 1.03 μm semiconductor laser and detection with a cooled InSb photodiode (or Ge photodiode for short wavelengths).…”

“…Next, MCT samples with x ~ 0.7 grown by various methods were subjected to comparative optical and structural studies [106][107][108]. MBE-grown material of this kind is now demanded for use in barrier, spacer and waveguide layers in multi-QW (MQW)-based MCT lasers (see, e.g., [63,64]). At the same time, MCT with x > 0.6 has never been studied in detail, as photodetectors operating at the corresponding wavelengths (0.8-1.5 µm) can be easily made from less expensive and more technologically advanced III-V semiconductors.…”

“…As MCT remains a material of choice for IR photodetectors [114], absorption-related optical methods appear to be much more important in this realm than PL. With the advent of MCT-based interband lasers [63,64], PL studies gain back some importance as a material study tool, but these devices seem to be far from practical implementation.…”