Asymmetric heterostructure for photovoltaic InAs quantum dot infrared photodetector

We present a study of the performance enhancement of a quantum dot infrared photodetector (QDIP), by means of complementary split-ring resonator (CSRR) nano-antennae. The QDIP is based on an asymmetric heterostructure containing a single layer of self-assembled InAs/GaAs quantum dots (QDs). The proximity of the QD plane to the top contact layer is exploited for the coupling with the near-field of the CSRR modes. The co-existence of the CSRR LC mode, at λLC = 7.4 μm, and of non-localized Bragg-like modes, is observed for the two-dimensional array of nano-antennae implemented on the QDIP. At λLC and a temperature T = 10 K, the antenna coupled device is characterized by a responsivity of 44 μA/W and a specific detectivity D* = 1.5 × 108Jones. For the highly localized LC mode, enhancements of a factor 1.7 in responsivity and 2.1 in specific detectivity are observed. Within the sub-wavelength LC mode effective surface, normalizing the overall response to the active surface of the detector, a responsivity enhancement of ∼19 is estimated, showing the potentiality of this approach for the realization of high-performance QDIPs working at normal incidence.

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confidence: 99%

Complementary split-ring resonator antenna coupled quantum dot infrared photodetector

Cerulo

Liverini

Fedoryshyn

et al. 2017

“…In Ref. 6, carrier injection from a quantum well reservoir to an active region comprising quantum dots was achieved by carrier tunneling through a blocking barrier. However, the bulk-like distribution of energy states and rather thick CBB in our device rule out the possibility of hole injection through tunneling.…”

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confidence: 99%

“…In recent years, significant attention has been paid to incorporating current blocking architectures into detector designs. For example, AlGaAs current blocking layers have been utilized in quantum dot IR photodetectors (QDIPs) both to enhance performance [1][2][3][4][5][6] and to achieve elevated operating temperatures. [7][8][9] Similarly, in type II InAs/ GaSb superlattice (T2SL) IR photodetectors, majority carrier (hole) blocking layers have been implemented, 10 as well as electron blocking and hole blocking unipolar barriers in complementary barrier infrared detectors (CBIRD) 11 and p-type-intrinsic-n-type (PbIbN) photodiodes.…”

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confidence: 99%

Effect of a current blocking barrier on a 2–6 μm p-GaAs/AlGaAs heterojunction infrared detector

Chauhan

Perera

et al. 2016

We report the performance of a 30 period p-GaAs/Al x Ga 1Àx As heterojunction photovoltaic infrared detector, with graded barriers, operating in the 2-6 lm wavelength range. Implementation of a current blocking barrier increases the specific detectivity (D*) under dark conditions by two orders of magnitude to $1.9 Â 10 11 Jones at 2.7 lm, at 77 K. Furthermore, at zero bias, the resistance-area product (R 0 A) attains a value of $7.2 Â 10 8 X cm 2 , a five orders enhancement due to the current blocking barrier, with the responsivity reduced by only a factor of $1.5. Published by AIP Publishing.[http://dx.doi.org/10.1063/1.4952431] Infrared (IR) detectors and imaging systems are becoming increasingly important in a diverse range of military and civilian applications. In recent years, significant attention has been paid to incorporating current blocking architectures into detector designs. For example, AlGaAs current blocking layers have been utilized in quantum dot IR photodetectors (QDIPs) both to enhance performance [1][2][3][4][5][6] and to achieve elevated operating temperatures. [7][8][9] Similarly, in type II InAs/ GaSb superlattice (T2SL) IR photodetectors, majority carrier (hole) blocking layers have been implemented, 10 as well as electron blocking and hole blocking unipolar barriers in complementary barrier infrared detectors (CBIRD) 11 and p-type-intrinsic-n-type (PbIbN) photodiodes. 12 Furthermore, dark current suppressing structures were also demonstrated, such as conduction band barriers in nBn photodetectors 13,14 and XBn barrier photodetectors. 15 In general, the main goal in these architectures is to lower the dark current, but with a relatively small compromise to the photocurrent, thus achieving a significant improvement in the specific detectivity (D*).Due to the mature growth and established processing technology of p-GaAs/Al x Ga 1Àx As, these materials systems have become increasingly attractive for demonstrating heterojunction interfacial workfunction IR photodetectors (HEIWIP), 16 which operate up to room temperature. 17 Furthermore, replacing the constant Al x Ga 1Àx As barrier with a graded barrier, achieved by tuning the Al mole fraction (x), was found to enable photovoltaic operation as well. 18 This is advantageous over photoconductive operation as it offers thermal noise limited performance and reduced power consumption. In this letter, we report the effect of a current blocking barrier (CBB) on a 30 period p-GaAs/Al x Ga 1Àx As IR detector with graded barriers, which shows a photoresponse at 77 K in the $2-6 lm range under photovoltaic operation. We observe an approximately five orders of magnitude higher resistance-area product (R 0 A) at zero bias, resulting in a two orders of magnitude improvement in D*, with the responsivity compromised only by a factor of $1.5 at zero bias, compared to performance without the CBB.A p-GaAs/Al x Ga 1Àx As heterojunction IR detector was grown on a semi-insulating GaAs substrate by molecular beam epitaxy 19 ( Fig. 1(a)). The active region of the ph...

“…Photovoltaic detectors are attractive for achieving (i) extremely low noise, (ii) high impedance, and (iii) low power dissipation, compared to photoconductive detectors. 1 Various device concepts based on p-n junctions, 2 quantum well (QW), 3 quantum dot (QD), 4,5 type-II InAs/GaSb, 6 and quantum cascade (QCD) structures 5,7 have been explored to implement photovoltaic operation. One of the key factors is to have a built-in potential to sweep photocarriers out of the active region without an external field.…”

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confidence: 99%

“…At zero bias where the shot noise vanishes, this expression is reduced to the normal form in terms of the Johnson noise. 4 With decreasing temperature, R diff rapidly increases for the bias around 0 V. To calculate photovoltaic D * at 80 K, extrapolation of R 0 in terms of the Arrhenius plots [ Fig. 2(b)] has been carried out.…”

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confidence: 99%

Wavelength-extended photovoltaic infrared photodetectors

Lao

Pitigala

Perera

et al. 2014

We report the incorporation of a long-wavelength photovoltaic response (up to 8 μm) in a short-wavelength p-type GaAs heterojunction detector (with the activation energy of EA∼0.40 eV), operating at 80 K. This wavelength-extended photovoltaic response is enabled by employing a non-symmetrical band alignment. The specific detectivity at 5 μm is obtained to be 3.5 × 1012 cm Hz1∕2/W, an improvement by a factor of 105 over the detector without the wavelength extension.