A Colloidal‐Quantum‐Dot Infrared Photodiode with High Photoconductive Gain

Tang, Yicheng; Wu, Feng; Chen, Fansheng; Zhou, Yi; Wang, Peng; Long, Mingsheng; Zhou, Wenjia; Ning, Zhijun; He, Jia; Gong, Fan; Zhu, Zhihong; Qin, Shiqiao; Hu, Weida

doi:10.1002/smll.201803158

Cited by 43 publications

(42 citation statements)

References 30 publications

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“…Due to the high work function of glassy‐graphene, the Dirac point of graphene has been shifted down to the conduction band, resulting in an Ohmic contact, in extreme difference from the conventional Schottky barrier contact of exfoliated graphene‐transition metal dichalcogenides (TMDs), which led to a high detectivity of ~1.8 × 10 10 Jones and regular responsivity of ~12.3 mA W −1 . Besides, surface or interface engineering can also improve the device performance . Du et al explored emerging heterostructures containing graphene and its fluorine‐functionalized derivative, which played an important role in broadband‐ and IR‐sensitive photodetectors.…”

Section: Two‐dimensional Heterostructuresmentioning

confidence: 99%

“…Besides, surface or interface engineering can also improve the device performance. 83 Du et al 52 explored emerging heterostructures containing graphene and its fluorine-functionalized derivative, which played an important role in broadband-and IRsensitive photodetectors. Fluorine-functionalized derivatives on the surface via plasma etching engineering were introduced into the system.…”

Section: Device Structures and Physical Mechanism For Photodetectionmentioning

confidence: 99%

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Two‐dimensional heterostructure promoted infrared photodetection devices

Rao

Wang

et al. 2019

InfoMat

123

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It is a rapidly developed subject in expanding the fundamental properties and application of two‐dimensional (2D) materials. The weak van der Waals interaction in 2D materials inspired researchers to explore 2D heterostructures (2DHs) based broadband photodetectors in the far‐infrared (IR) and middle‐IR regions with high response and high detectivity. This review focuses on the strategy and motivation of designing 2DHs based high‐performance IR photodetectors, which provides a wide view of this field and new expectation for advanced photodetectors. First, the photocarriers' generation mechanism and frequently employed device structures are presented. Then, the 2DHs are divided into semimetal/semiconductor 2DHs, semiconductor/semiconductor 2DHs, and multidimensional semi‐2DHs; the advantages, motivation, mechanism, recent progress, and outlook are discussed. Finally, the challenges for next‐generation photodetectors are described for this rapidly developing field.

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Section: Two‐dimensional Heterostructuresmentioning

confidence: 99%

Section: Device Structures and Physical Mechanism For Photodetectionmentioning

confidence: 99%

Two‐dimensional heterostructure promoted infrared photodetection devices

Rao

Wang

et al. 2019

InfoMat

123

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“…They demonstrated a fast response speed with electron drift by built‐in potential derived from the difference in work functions, recording 300 ns drift transit time which had been the fastest to date . In addition to manipulating the energy level alignment between the interfaces, chemical treatments such as QD surface ligand control had been proposed as one of means to improve the response speed of QD photodiodes . In the aspect of device physics, QD's surface ligands form an insulating shell that retards charge transport between nanoparticle film and the surrounding device layers .…”

Section: Introductionmentioning

confidence: 99%

“…In the aspect of device physics, QD's surface ligands form an insulating shell that retards charge transport between nanoparticle film and the surrounding device layers . Other experimental studies on charge transport in inorganic nanocrystal films have revealed that the charge carrier mobility increases exponentially with the decrease of ligand length . In this point of view, many studies attempted to enhance inter‐QD coupling by using shorter ligand molecules, and improve electrical properties of QD films …”

Section: Introductionmentioning

confidence: 99%

High‐Speed Colloidal Quantum Dot Photodiodes via Accelerating Charge Separation at Metal–Oxide Interface

Jeong

Kyhm

Kyu

et al. 2019

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industrial robots, or building managements. With the IoT's intrinsic nature of individual machines observing their surroundings and communicating the status with one another, [1] one of the key challenges in the field becomes the sensors. Accordingly, many different sensors such as thermal, [2] piezoelectric, [3] or strain sensors [2,4] have been researched and developed in diverse fields. Among the various sensors, we focus on high-speed optical sensor for obtaining both fast-and high-resolution imaging using colloidal quantum dots (QDs) as light sensing material.Colloidal QDs, semiconductor nanocrystals with size-dependent tunable bandgap, [5][6][7][8][9] are considered as a promising material for future device applications such as transparent [10][11][12] or flexible/stretchable opto-electronics. [13,14] For their low manufacturing cost, large-area applicability, solution processability, [8] and spectral tunability through quantum size effect, QD-based devices have achieved rapid development among a wide variety of emerging optics and electronic technologies [5,6] over the last decade.One of the efforts on developing QD-based devices has been on investigating well-performing QD-based photodiodes. [9,[15][16][17] In recent years, the understanding of the underlying physics in the operation of QD photodiodes, specifically the factors that limit their performance, has been greatly improved. [9,[15][16][17] However, it has been difficult to improve the response speed of QD-based opto-electronic detectors due to the poor transport properties of the QDs arising from geometrical and physical properties such as interparticle spacings, [5,6,9] quantum confinement effect that induces strong coupling between the photogenerated electron-hole pair to the QDs, [7,18,19] and coreshell structure of the QDs which excited charge carriers must tunnel through to the electrodes because the quantum well structure for confinement behaves as electrical intervening factor. [20][21][22] Some recent studies of QD-based opto-electronic detectors have suggested that the speed of the device can be improved by introducing the Schottky barrier between QD film and electrode layer, effectively bending the electronic bands at the interface. [9,17,[23][24][25] Oertel et al. [9] and Clifford et al. [17] demonstrated fast response of QD-based photodiodes by forming a Schottky barrier at the interface between QD film and metal contact. They demonstrated a fast response speed with electron drift by With ever-growing technological demands in the imaging sensor industry for autonomous driving and augmented reality, developing sensors that can satisfy not only image resolution but also the response speed becomes more challenging. Herein, the focus is on developing a high-speed photosensor capable of obtaining high-resolution, high-speed imaging with colloidal quantum dots (QDs) as the photosensitive material. In detail, high-speed QD photodiodes are demonstrated with rising and falling times of τ r = 28.8 ± 8.34 ns and τ f = 40 ± 9.81 ns, respectively,...

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“…However, all curves cross at nearly the same point, indicating that the zero responsivity point is independent of the incident intensity. It was reported in other studies on other photodetectors with a single photogate that the relation between the photocurrent I ph and incident intensity P can be expressed as follows

I_{ph} \propto P^{α}

where α is a fitting parameter related to the gate voltage biases. In our proposed MoS 2 /HfO 2 /SOI device, two photogates are presented in the top MoS 2 film and Si substrate; thus, this equation can be rewritten as follows

I_{ph} \propto P^{α} - P^{β}

where I ph is the net photocurrent induced by dual‐photogating effects.…”

Section: Resultsmentioning

confidence: 99%

MoS₂/HfO₂/Silicon‐On‐Insulator Dual‐Photogating Transistor with Ambipolar Photoresponsivity for High‐Resolution Light Wavelength Detection

Deng

Zong

Zhu

et al. 2019

Adv Funct Materials

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Photogating detectors based on 2D materials attract significant research interests. However, most of these photodetectors are only sensitive to the incident intensities and lack the ability to distinguish different wavelengths. Color imaging based on these detectors usually requires additional optical filter arrays to collect red, green, and blue (RGB) colors in different photodetectors to restore the true color of one pixel. In this study, an MoS2/HfO2/silicon‐on‐insulator field effect phototransistor with wavelength distinguishing ability is presented, where the photogating effect can be simultaneously formed in the top MoS2 gate and bottom Si substrate gate. These two individual photogating effects can reduce and increase the read current in the middle 12 nm Si channel, respectively. Thus, by tuning the applied voltages on these two gates, the device can be used to obtain tunable ambipolar photoresponsivity from +7000 A W−1 (Si bottom gate dominated) to 0 A W−1 (balanced), and finally to −8000 A W−1 (MoS2 gate dominated). In addition, the experimental results show that the corresponding top gate voltage to the zero responsivity (0 A W−1) point can be positively shifted by the increasing of incident wavelength with high resolution up to 2 nm and is insensitive to the incident intensity.

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A Colloidal‐Quantum‐Dot Infrared Photodiode with High Photoconductive Gain

Abstract: on solution-processed semiconductors. Compared to them, our device shows significant merits on R and EQE that may enable more applications.

Cited by 43 publications

References 30 publications

Two‐dimensional heterostructure promoted infrared photodetection devices

Two‐dimensional heterostructure promoted infrared photodetection devices

High‐Speed Colloidal Quantum Dot Photodiodes via Accelerating Charge Separation at Metal–Oxide Interface

MoS₂/HfO₂/Silicon‐On‐Insulator Dual‐Photogating Transistor with Ambipolar Photoresponsivity for High‐Resolution Light Wavelength Detection

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A Colloidal‐Quantum‐Dot Infrared Photodiode with High Photoconductive Gain

Abstract: on solution-processed semiconductors. Compared to them, our device shows significant merits on R and EQE that may enable more applications.

Cited by 43 publications

References 30 publications

Two‐dimensional heterostructure promoted infrared photodetection devices

Two‐dimensional heterostructure promoted infrared photodetection devices

High‐Speed Colloidal Quantum Dot Photodiodes via Accelerating Charge Separation at Metal–Oxide Interface

MoS2/HfO2/Silicon‐On‐Insulator Dual‐Photogating Transistor with Ambipolar Photoresponsivity for High‐Resolution Light Wavelength Detection

Contact Info

Product

Resources

About

MoS₂/HfO₂/Silicon‐On‐Insulator Dual‐Photogating Transistor with Ambipolar Photoresponsivity for High‐Resolution Light Wavelength Detection