Conduction band resonant states absorption for quantum dot infrared detectors operating at room temperature

TL;DR

This paper introduces a novel quantum dot infrared detector design that leverages conduction band resonant states to significantly improve room temperature detection capabilities, overcoming previous limitations of quantum dot devices.

Contribution

It presents a new approach exploiting resonant states in quantum dots to enhance carrier extraction, demonstrated through both theoretical analysis and experimental validation.

Findings

Room temperature operation with high detectivity achieved.

Resonant states significantly improve carrier extraction.

Potential to surpass existing quantum dot infrared detectors.

Abstract

Long Wavelenght infrared devices, despite growing interest due to a wide range of applications in commercial, public, and academic sectors, are still struggling to achieve significant improvements over well-established technologies like HgCdTe detectors. Devices based on quantum nanostructures remain non competitive due to unresolved drawbacks, the most significant being the need to cool down to liquid nitrogen temperatures to improve the signal-to-noise ratio. In this work, we demonstrate an innovative solution to surpass the current generation of quantum dot-based detectors by exploiting the absorption from quantum dot localized states to resonant states in the continuum, that is states in the semiconductor conduction band with an enhanced probability density in the quantum dot region. This unprecedented approach takes advantage of the unique properties of such states to massively enhance carrier extraction, allowing to overcome one of the most crucial drawbacks of quantum dot-based infrared detectors. This innovative solution is discussed here from both theoretical and experimental perspectives. The measured room temperature operation with high detectivity demonstrates that exploiting resonant states absorption in quantum dots offers the long-sought solution for the next generation of infrared photodetectors.