Bound-to-continuum absorption with tunneling in type-II nanostructures: a multiband source-radiation approach

Area of Science:

• Semiconductor physics
• Quantum mechanics
• Materials science

Background:

• Type-II semiconductor quantum wells exhibit complex optical absorption phenomena.
• Understanding the interplay between quantum tunneling and optical transitions is crucial for device performance.

Purpose of the Study:

• To develop a novel method for calculating bound-to-continuum absorption in type-II quantum wells.
• To incorporate quantum tunneling effects into optical transition calculations.
• To evaluate tunneling rates and absorption strengths for photovoltaic applications.

Main Methods:

• Utilizing the effective-mass approximation with band mixing.
• Employing perfectly matched layers based on the eight-band Luttinger-Kohn Hamiltonian.
• Analyzing Fano resonance lineshapes to extract physical parameters.

Main Results:

• Successfully converted bound-to-continuum absorption calculations into a source-radiation problem.
• Fully accounted for the interplay between quantum tunneling and optical transitions.
• Enabled evaluation of tunneling rates and relative absorption strengths from Fano resonance features.

Conclusions:

• The developed approach accurately models optical absorption in type-II quantum wells.
• The method provides a pathway for estimating carrier extraction rates in nanostructures.
• This research is valuable for optimizing type-II nanostructures in photovoltaic devices.