Radiative recombination in narrow gap HgTe/CdHgTe quantum well heterostructures for laser applications

Area of Science:

• Solid State Physics
• Quantum Optics
• Materials Science

Background:

• Radiative recombination is a key process in semiconductor optoelectronic devices.
• Cadmium Mercury Telluride/Mercury Telluride (CdHgTe/HgTe) quantum wells are promising for long-wavelength infrared applications.
• Understanding recombination dynamics is crucial for optimizing device performance.

Purpose of the Study:

• To investigate radiative recombination in CdHgTe/HgTe quantum wells with bandgaps between 40-140 meV.
• To analyze the influence of valence band structure on radiative recombination efficiency.
• To identify strategies for enhancing recombination for laser development.

Main Methods:

• Utilized a four-band Kane model for theoretical calculations.
• Calculated radiative lifetimes within the quantum wells.
• Compared theoretical results with experimental photoconductivity kinetics measurements.

Main Results:

• Calculated radiative lifetimes showed good agreement with experimental measurements.
• Identified side maxima in the valence band as a limiting factor for radiative recombination at high carrier concentrations.
• Demonstrated that these valence band features significantly hinder recombination efficiency.

Conclusions:

• The four-band Kane model accurately predicts radiative lifetimes in CdHgTe/HgTe quantum wells.
• Valence band structure critically impacts radiative recombination, especially at high carrier densities.
• Strategies to mitigate the hindering effect of valence band maxima are necessary for advancing long-wavelength laser technology.