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Quantum Dot Infrared Photodetectors: Photoresponse Enhancement Due to Potential Barriers

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ABSTRACT

Potential barriers around quantum dots (QDs) play a key role in kinetics of photoelectrons. These barriers are always created, when electrons from dopants outside QDs fill the dots. Potential barriers suppress the capture processes of photoelectrons and increase the photoresponse. To directly investigate the effect of potential barriers on photoelectron kinetics, we fabricated several QD structures with different positions of dopants and various levels of doping. The potential barriers as a function of doping and dopant positions have been determined using nextnano3 software. We experimentally investigated the photoresponse to IR radiation as a function of the radiation frequency and voltage bias. We also measured the dark current in these QD structures. Our investigations show that the photoresponse increases ~30 times as the height of potential barriers changes from 30 to 130 meV.

No MeSH data available.


Normal incidence relative spectral photoresponse versus barrier height of samples B44, B45, B52, B53, and B54 at T = 80 K.
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Figure 9: Normal incidence relative spectral photoresponse versus barrier height of samples B44, B45, B52, B53, and B54 at T = 80 K.

Mentions: In Figure 9 we summarize our main results. As seen, when the height of the potential barriers in the selected devices changes from 28 to 130 meV, the photoresponse increases exponentially as a function of the barrier height [6-9]. At high doping level (the sample B54), the effect is saturated. We observed ~30 times enhancement of the photoresponse due to potential barriers around dots. Our results show that QDIPs can substantially outperform quantum-well photodetectors due to the manageable photocarrier kinetics, which can be controlled by potential barriers.


Quantum Dot Infrared Photodetectors: Photoresponse Enhancement Due to Potential Barriers
Normal incidence relative spectral photoresponse versus barrier height of samples B44, B45, B52, B53, and B54 at T = 80 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211266&req=5

Figure 9: Normal incidence relative spectral photoresponse versus barrier height of samples B44, B45, B52, B53, and B54 at T = 80 K.
Mentions: In Figure 9 we summarize our main results. As seen, when the height of the potential barriers in the selected devices changes from 28 to 130 meV, the photoresponse increases exponentially as a function of the barrier height [6-9]. At high doping level (the sample B54), the effect is saturated. We observed ~30 times enhancement of the photoresponse due to potential barriers around dots. Our results show that QDIPs can substantially outperform quantum-well photodetectors due to the manageable photocarrier kinetics, which can be controlled by potential barriers.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Potential barriers around quantum dots (QDs) play a key role in kinetics of photoelectrons. These barriers are always created, when electrons from dopants outside QDs fill the dots. Potential barriers suppress the capture processes of photoelectrons and increase the photoresponse. To directly investigate the effect of potential barriers on photoelectron kinetics, we fabricated several QD structures with different positions of dopants and various levels of doping. The potential barriers as a function of doping and dopant positions have been determined using nextnano3 software. We experimentally investigated the photoresponse to IR radiation as a function of the radiation frequency and voltage bias. We also measured the dark current in these QD structures. Our investigations show that the photoresponse increases ~30 times as the height of potential barriers changes from 30 to 130 meV.

No MeSH data available.