Limits...
Quantum Dot Infrared Photodetectors: Photoresponse Enhancement Due to 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.


Dark current density of samples B52–B54 at T = 80 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211266&req=5

Figure 5: Dark current density of samples B52–B54 at T = 80 K.

Mentions: Dark current densities for samples B52, B53, and B54 are presented in Figure 5. The dark current density in the sample B54 is higher by two orders of magnitude than that in the sample B53 and by four orders of magnitude higher than that in B52. Let us note that the current–voltage characteristic for the sample B52 is more symmetrical than that for samples B53 and B54. The asymmetric characteristic of this sample is due to 40 nm GaAs undoped layer at the substrate side.


Quantum Dot Infrared Photodetectors: Photoresponse Enhancement Due to Potential Barriers
Dark current density of samples B52–B54 at T = 80 K.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Dark current density of samples B52–B54 at T = 80 K.
Mentions: Dark current densities for samples B52, B53, and B54 are presented in Figure 5. The dark current density in the sample B54 is higher by two orders of magnitude than that in the sample B53 and by four orders of magnitude higher than that in B52. Let us note that the current–voltage characteristic for the sample B52 is more symmetrical than that for samples B53 and B54. The asymmetric characteristic of this sample is due to 40 nm GaAs undoped layer at the substrate side.

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.