Optical absorption engineering in two-dimensional quantum rings: design and optimization for FIR to MIR detection applications

In this work, we present the new photodetector based on snowflake quantum rings (QRs) structure utilizing a two-dimensional tight-binding model. Optical absorption has calculated and compared with different usual geometries of rectangular, triangular and circular QRs. There are narrow dominant peaks in the absorption spectrum with a low FHWM of 15 meV in the range of 50 meV in the far-infrared (FIR) regime to 300 meV in the mid-infrared (FIR) regime. The two-dimensional confining potential for Koch shaped quantum ring had been described in previous work was inserted in the tight-binding method and probability density of nine lowest electron energy states and absorption have calculated for the first time. Using these results, some properties of QRs were predicted and their validity was examined and displayed further. For a Koch shape quantum ring, there is fine displacement about 3 meV in absorption peak in long-wavelength infrared regime with changing iteration number that can be used for fine-tuning of the absorption spectrum. Also, a circular ring with minimal energy states has absorption peaks with an average full width at half maximum of 12.5 meV that can be tuned with the resolution of 13 meV in the FIR regime. These results are more applicable for an experimentalist to design a new photodetector with a narrower sharp peak for applications like night-vision, a thermal detector, and total IR absorbers.

Automated summary

In this study, a new photodetector based on snowflake quantum rings (QRs) structure was presented and analyzed using a two-dimensional tight-binding model. The results showed narrow dominant absorption peaks with low full width at half maximum (FHWM) in the far-infrared (FIR) and mid-infrared (FIR) regimes. The properties and tuning capabilities of QRs were examined and demonstrated using the probability density and absorption calculations for different quantum ring geometries.