Near Unity Absorption in Nanocrystal Based Short Wave Infrared Photodetectors Using Guided Mode Resonators

Chu, Audrey; Gréboval, Charlie; Goubet, Nicolas; Martinez, Bertille; Livache, Clément; Qu, Junling; Rastogi, Prachi; Bresciani, Francesco Andrea; Prado, Yoann; Suffit, Stéphan; Ithurria, Sandrine; Vincent, Grégory; Lhuillier, Emmanuel

doi:10.1021/acsphotonics.9b01015

Cited by 54 publications

(79 citation statements)

References 57 publications

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“…Regardless of the particle sizes or the surface chemistries, all samples fit with n = 2.35 ± 0.15. This value is larger than the one conveniently used in the electromagnetic design (n = 2) [22,24] but matches well with the value recently used by Tang et al [38] This encourages a clear update of the input parameters for future simulation works. It is also worth noticing that the surface chemistry/film deposition method (see Figures S5, S7, and S8, Supporting Information) plays a larger role in the final n value than the particle size: a change in the film preparation can reduce the refractive index by 0.2 (Figure S8, Supporting Information).…”

Section: Revealing the Complex Optical Index Of Hgte Nc Thin Filmssupporting

confidence: 84%

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Complex Optical Index of HgTe Nanocrystal Infrared Thin Films and Its Use for Short Wave Infrared Photodiode Design

Rastogi

Chu

Dang

et al. 2021

Advanced Optical Materials

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semiconductors, colloidal NCs simplify the coupling to the read-out circuit [9][10][11] (i.e., no hybridization step through indium bumps). Beyond the cost reduction, it also eases pixel pitch reduction, bringing it closer to the diffraction limit, [12,13] from 15 to 5 µm typically.Among potential material candidates, HgTe offers the widest spectral tunability. It can be grown under highly confined forms such as nanoplatelets [14][15][16] with bandedge around 800 nm, or as larger sizes (≫Bohr radius) with NCs absorbing in the THz range. [17,18] Over the recent years, significant progresses have been made on the device performance as their geometries have been improved. Compared to initial poorly ligand-exchanged films deposited on interdigitated electrodes, complex photodiodes, [4,19] and phototransistors presenting a reduced dark current and an enhanced photocarrier dissociation are now proposed. The control of the light-matter coupling is certainly one of the directions that have led to the most recent improvements. Cavities [20,21] and plasmonic resonators [22][23][24] have been introduced to obtain strongly-absorbing thin films. The interest for the light-matter coupling control is not only limited to the material absorption. It also raises interest in light emission [25] and also potentially in lasing regarding the The limited investigation of the optical properties of HgTe nanocrystal (NC) thin films has become a bottleneck for the electromagnetic design of devices.Using broadband ellipsometry, the refractive index (n) and the extinction coefficient (k) are determined for a series of HgTe NC films relevant to infrared sensing applications. Electromagnetic simulations reveal that the n value of HgTe NC thin films can conveniently be approximated by its mean spectral value n = 2.35 ± 0.15. This complex optical index is then used to design a diode with i) a reduced amount of Hg containing material (thin film < 150 nm) and ii) a thickness of the device better-matched with the carrier diffusion length. It is demonstrated that introducing an aluminum grating onto the transparent conductive electrode leads to an enhanced absorption while reinforcing the work-function difference between the two electrodes. Broadband (≈1 µm), non-polarized, and strong absorption up to 100% is designed. This leads to a responsivity of 0.2 A W −1 and a detectivity of 2 × 10 10 Jones for 2 µm cut-off wavelength at room-temperature, while the time response is as short as 110 ns.

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Section: Revealing the Complex Optical Index Of Hgte Nc Thin Filmssupporting

confidence: 84%

“…The control of the light-matter coupling is certainly one of the directions that have led to the most recent improvements. Cavities [20,21] and plasmonic resonators [22][23][24] have been introduced to obtain strongly-absorbing thin films. The interest for the light-matter coupling control is not only limited to the material absorption.…”

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confidence: 99%

Complex Optical Index of HgTe Nanocrystal Infrared Thin Films and Its Use for Short Wave Infrared Photodiode Design

Rastogi

Chu

Dang

et al. 2021

Advanced Optical Materials

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“…Progresses on both material growth 2 – 6 and device design 7 transformed HgTe NCs into a versatile platform for IR optoelectronics 8 . Key developments include on-chip integration 9 , coupling to resonators to achieve strongly-absorbing devices 10 – 14 and hybridization to read out circuits to design focal plane arrays operating in the short-wave 15 , 16 and mid-wave IR 17 , 18 .…”

Section: Introductionmentioning

confidence: 99%

Infrared photoconduction at the diffusion length limit in HgTe nanocrystal arrays

et al. 2021

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Narrow band gap nanocrystals offer an interesting platform for alternative design of low-cost infrared sensors. It has been demonstrated that transport in HgTe nanocrystal arrays occurs between strongly-coupled islands of nanocrystals in which charges are partly delocalized. This, combined with the scaling of the noise with the active volume of the film, make case for device size reduction. Here, with two steps of optical lithography we design a nanotrench which effective channel length corresponds to 5–10 nanocrystals, matching the carrier diffusion length. We demonstrate responsivity as high as 1 kA W−1, which is 105 times higher than for conventional µm-scale channel length. In this work the associated specific detectivity exceeds 1012 Jones for 2.5 µm peak detection under 1 V at 200 K and 1 kHz, while the time response is as short as 20 µs, making this performance the highest reported for HgTe NC-based extended short-wave infrared detection.

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“…First, diffraction gratings that consist of 650 nm wide and 240 nm deep trenches with period of 2 µm were imprinted on CQDs (Figure S12, Supporting Information). Diffraction grating structures have been experimentally demonstrated in CQD solar cells and infrared detectors to enhance light absorption. Simulation results also confirm that an absorption enhancement ratio above 2 can be obtained at tunable wavelengths by patterning the CQDs (Figure S13, Supporting Information).…”

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Direct Imprinting of Quasi‐3D Nanophotonic Structures into Colloidal Quantum‐Dot Devices

et al. 2020

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Three‐dimensional (3D) subwavelength nanostructures have emerged and triggered tremendous excitement because of their advantages over the two‐dimensional (2D) counterparts in fields of plasmonics, photonic crystals, and metamaterials. However, the fabrication and integration of 3D nanophotonic structures with colloidal quantum dots (CQDs) faces several technological obstacles, as conventional lithographic and etching techniques may affect the surface chemistry of colloidal nanomaterials. Here, the direct fabrication of functional quasi‐3D nanophotonic structures into CQD films is demonstrated by one‐step imprinting with well‐controlled precision in both vertical and lateral directions. To showcase the potential of this technique, diffraction gratings, bilayer wire‐grid polarizers, and resonant metal mesh long‐pass filters are imprinted on CQD films without degrading the optical and electrical properties of CQD. Furthermore, a dual‐diode CQD detector into an unprecedented mid‐wave infrared two‐channel polarization detector is functionalized by embedding an imprinted bilayer wire‐grid polarizer within the CQDs. The results show that this approach offers a feasible pathway to combine quasi‐3D nanostructures with colloidal materials‐based optoelectronics and access a new level of light manipulation.

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Near Unity Absorption in Nanocrystal Based Short Wave Infrared Photodetectors Using Guided Mode Resonators

Cited by 54 publications

References 57 publications

Complex Optical Index of HgTe Nanocrystal Infrared Thin Films and Its Use for Short Wave Infrared Photodiode Design

Complex Optical Index of HgTe Nanocrystal Infrared Thin Films and Its Use for Short Wave Infrared Photodiode Design

Infrared photoconduction at the diffusion length limit in HgTe nanocrystal arrays

Direct Imprinting of Quasi‐3D Nanophotonic Structures into Colloidal Quantum‐Dot Devices

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