Broadband and photovoltaic THz/IR response in the GaAs-based ratchet photodetector.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35613269.
- Also identified by DOI 10.1126/sciadv.abn2031 and PMC identifier 9132437.
- Licence recorded as CC BY-NC.
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Abstract
High-performance broadband infrared (IR)/terahertz (THz) detection is crucial in many optoelectronic applications. However, the spectral response range of semiconductor-based photodetectors is limited by the bandgaps. This paper proposes a ratchet structure based on the GaAs/Al<i><sub>x</sub></i>Ga<sub>1-<i>x</i></sub>As heterojunction, where the quasi-stationary hot hole distribution and intravalence band absorption from light or heavy hole states to the split-off band overcome the bandgap limit, ensuring an ultrabroadband photoresponse from near-IR to THz region (4 to 300 THz). The peak responsivity of the proposed structure can reach 7.3 A/W, which is five orders of magnitude higher than that of the existing broadband photon-type detector. Because of the ratchet effect, the proposed photodetector has a bias-tunable photoresponse characteristic and can operate in the photovoltaic mode with a broad photocurrent spectrum (18 to 300 THz). This work not only demonstrates a broadband photon-type THz/IR photodetector but also provides a method to study the light-responsive ratchet.