Broadband image sensor array based on graphene–CMOS integration

In the past decade, high-performance, low-cost, and robust photodetectors have become one of the key components for a wide range of commercial systems, including environment and security monitoring, [1] wearable electronics, [2] free-space communications, [3] and biomedical diagnostics, [4] etc. As inspired by these applications, various emerging materials, such as quantum dots, [5] carbon nanotubes, [6] graphene, [7] and transition-metal dichalcogenides, [8] are extensively explored for the efficient photodetection. In particular, organic-inorganic hybrid perovskites (OHPs) are lately considered as the superior light-harvesting materials for photodetectors owning to their unique advantages of high optical absorption coefficient, long exciton diffusion length, and low binding energy of exciton. [9][10][11] Although these OHP materials can be easily prepared by cost-effective solution-based processes to meet the ever-increasing consumer demands for large-area and flexible optoelectronics, their photodetectors usually exhibit the relatively low responsivity because of the limited carrier mobility as well as the absence of photoconductive gain (G) mechanism that can induce multiple charge carriers by one incident photon.In order to tackle these insufficient device performances, hybrid phototransistors by simply integrating perovskites (PVKs) with different 2D materials (e.g., graphene, [12] black phosphorus, [13,14] MoS 2 , [15] and WSe 2 [16] ) have been proposed and demonstrated. By using these hybrid heterostructures, upon illumination, the photoexcited charge carriers can be spatially separated at the hetero-interface in order to prolong their carrier lifetimes, which subsequently improves the photoconductive gain of the system. However, there are still significant concerns regarding the high fabrication cost and low production yield of 2D materials for the realization of such photodetectors. At the same time, due to the low formation energy, PVK photodetectors are generally susceptible to degradation upon air and moisture exposure. In this case, tremendous efforts have then been invested to explore effective approaches to enhance the ambient-stability of these devices. [17,18] Among many latest advances, recent breakthroughs in achieving the 2D Ruddlesden-Popper phase of PVKs with the chemical formula of (RNH 3 ) 2 (A) n−1 M n X 3n+1 , where RNH 3 is a large size or long-chain organic cation, A is a regular cation, M is a divalent Organic-inorganic hybrid perovskites (PVKs) have recently emerged as attractive materials for photodetectors. However, the poor stability and low electrical conductivity still restrict their practical utilization. Owing to the quantum-well feature of two-dimensional (2D) Ruddlesden-Popper PVKs (2D PVKs), a promising quasi-2D PVK/indium gallium zinc oxide (IGZO) heterostructure phototransistor can be designed. By using a simple ligand-exchange spin-coating method, quasi-2D PVK fabricated on flexible substrates exhibits a desirable type-II energy band alignment, which facilitates effect...

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confidence: 99%

Flexible Quasi‐2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

et al. 2019

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“…In comparison with the state of art rigid photodetector, the strategies and processing methods to produce high optoelectronic key performance metrics are still underdeveloped . Hybrid graphene photodetectors have achieved responsivities of 10 7 A W −1 and detectivity of 10 7 , while still maintaining a response time from 0.1 to 1 ms . TMDs have also reached a value of 1.8 × 10 5 A W −1 and detectivity higher than 10 14 for WSe 2 and similarly to graphene, they have also been combined with other semiconductors to enhance even further their responsivity 6 × 10 5 A W −1 and detectivity 7 × 10 14 .…”

Section: Discussionmentioning

confidence: 99%

Flexible Photodetector Based on 2D Materials: Processing, Architectures, and Applications

Dong

Simões

Yang

2020

Adv Materials Inter

148

111

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Flexible photodetectors have emerged during the past few years for applications in healthcare, security, and environmental monitoring. Recently, 2D materials have started being implemented as functional layers in flexible photodetector due to their outstanding optoelectronic characteristics paired with high mechanical flexibility. In this work, the authors analyze the progress of 2D material‐based flexible photodetectors architectures, with a focus on graphene family, (Di)chalcogenides and van der Waals heterostructures. The optical and mechanical characteristics of 2D materials flexible photodetectors are systematically analyzed. Furthermore, the processing techniques compatible with flexible substrates and proof‐of‐concept sensors integrating 2D material flexible photodetectors are also reviewed. In the last section, the remaining challenges and future perspectives are discussed, envisioning to support future developments in the field.

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“…[43] However, the PbS quantum dots were spun on the surface of silicon IC chips and that was not CMOS compatible fabrication process. Currently, extensive attention has been given to the integration of CMOScompatible IR photodetectors and signal processing circuits on a single chip for affordable IR optical receivers and image sensors.…”

Section: Wwwadvmattechnoldementioning

confidence: 99%

Performance Enhancement of Graphene Photodetectors via In Situ Preparation of TiO₂ on Graphene Channels

Cheng

Yang

Huang

et al. 2018

Adv Materials Technologies

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modulators, [14,15] and photodetectors. [16][17][18][19][20] The combination of a broadband lightabsorption range (from far-infrared to ultraviolet ranges in theory [21] ) and ultrahigh carrier mobility (1 000 000 cm 2 V −1 s −1 in experiment [22] ) makes graphene a star contender for photodetection applications. [16][17][18][19][20]23] The first reported spatial graphene photodetector (GPD) achieved a bandwidth of ≈40 GHz, and the ultrahigh intrinsic operation speeds could be well over 500 GHz, surpassing state-of-the-art PDs based on other materials. [16] However, the uniform 2.3% optical absorption of graphene limits the photoresponsivity of GPDs to several mA W −1 . [16,17] To enhance the optical absorption of graphene and thus the photoresponsivity of GPDs, microcavities, [24] plasmon resonators, [25] and silicon optical waveguides [18][19][20]26,27] have been utilized, but these structures weaken the broadband characteristic of GPDs. Another method carried out by fabricating a hybrid photodetector consisting of graphene covered by a thin film of colloidal quantum dots greatly improves the photoresponsivity from visible to near-infrared ranges. [28] However, the operation stability of this kind of GPD may not be satisfactory due to the air instability of colloidal quantum dots and the "dirty" interface between graphene and the cover layer. Moreover, colloidal quantum dots cannot be obtained with complementary metal-oxide-semiconductor (CMOS)-compatible fabrication processes, which are critical for low-cost devices. Hence, new methods should be proposed to achieve a CMOS-compatible broadband GPD with high photoresponsivity and high operation stability.TiO 2 nanomaterials have attracted considerable attention for applications in optoelectronic devices, [29] solar cells, [30] and photocatalysts [31] due to their advantages such as nontoxicity, low cost, chemical and thermal stability, and resistance to photocorrosion. [32][33][34] TiO 2 nanomaterials have been widely used as a shielding layer to prevent penetration of water molecules and oxygen gas. [35,36] Thus, thin TiO 2 films with low gas permeabilities can be excellent protection layers for graphene in high-stability GPDs. TiO 2 has three polymorphs: rutile, anatase, and brookite. [37] The metastable anatase form shows better performance in energy-related applications and optoelectronics because its formation temperature is relatively low and numerous intrinsic point defects exist in incomplete lattices. [38] Photodetectors Graphene, a single sheet of carbon atoms in a hexagonal lattice, [1] has captured extensive research interest due to its excellent mechanical, [2] thermal, [3] electronic, [1,4] and optical properties. [5,6] Due to its unique band structure, graphene shows ultrahigh carrier mobility, tunable transport polarity, and tunable broadband absorption, which make graphene a very promising candidate for use in electronic, photonic, and optoelectronic applications, such as transistors, [7] frequency multipliers, [8,9] frequency mixers, [10][11][1...

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Broadband image sensor array based on graphene–CMOS integration

Cited by 608 publications

References 38 publications

Flexible Quasi‐2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

Flexible Quasi‐2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

Flexible Photodetector Based on 2D Materials: Processing, Architectures, and Applications

Performance Enhancement of Graphene Photodetectors via In Situ Preparation of TiO₂ on Graphene Channels

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Broadband image sensor array based on graphene–CMOS integration

Cited by 608 publications

References 38 publications

Flexible Quasi‐2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

Flexible Quasi‐2D Perovskite/IGZO Phototransistors for Ultrasensitive and Broadband Photodetection

Flexible Photodetector Based on 2D Materials: Processing, Architectures, and Applications

Performance Enhancement of Graphene Photodetectors via In Situ Preparation of TiO2 on Graphene Channels

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Performance Enhancement of Graphene Photodetectors via In Situ Preparation of TiO₂ on Graphene Channels