MoS2 Based Photodetectors: A Review

Wang H., Wang X., Chen Y., Zhang S., Jiang W., Zhang X., Qin J., Wang J., Li X., Pan Y., Liu F., Shi Z., Zhang H., Tu L., Wang H., et. al.

Nakotte T., Luo H., Pietryga J.

Hybrid lead chalcogenide (PbE) (E = S, Se) quantum dot (QD)-layered 2D systems are an emerging class of photodetectors with unique potential to expand the range of current technologies and easily integrate into current complementary metal-oxide-semiconductor (CMOS)-compatible architectures. Herein, we review recent advancements in hybrid PbE QD-layered 2D photodetectors and place them in the context of key findings from studies of charge transport in layered 2D materials and QD films that provide lessons to be applied to the hybrid system. Photodetectors utilizing a range of layered 2D materials including graphene and transition metal dichalcogenides sensitized with PbE QDs in various device architectures are presented. Figures of merit such as responsivity (R) and detectivity (D*) are reviewed for a multitude of devices in order to compare detector performance. Finally, a look to the future considers possible avenues for future device development, including potential new materials and device treatment/fabrication options.

Li M., Yao J., Wu X., Zhang S., Xing B., Niu X., Yan X., Yu Y., Liu Y., Wang Y.

Molybdenum disulfide (MoS2) with excellent properties has been widely reported in recent years. However, it is a great challenge to achieve p-type conductivity in MoS2 because of its native stubborn n-type conductivity. Substitutional transition metal doping has been proved to be an effective approach to tune their intrinsic properties and enhance device performance. Herein, we report the growth of Nb-doping large-area monolayer MoS2 by a one-step salt-assisted chemical vapor deposition method. Electrical measurements indicate that Nb doping suppresses n-type conductivity in MoS2 and shows an ambipolar transport behavior after annealing under the sulfur atmosphere, which highlights the p-type doping effect via Nb, corresponding to the density functional theory calculations with Fermi-level shifting to valence band maximum. This work provides a promising approach of two-dimensional materials in electronic and optoelectronic applications.

Liu Y., Gao Y., Zhang S., He J., Yu J., Liu Z.

Valley degree of freedom in the first Brillouin zone of Bloch electrons offers an innovative approach to information storage and quantum computation. Broken inversion symmetry together with the presence of time-reversal symmetry endows Bloch electrons non-zero Berry curvature and orbital magnetic moment, which contribute to the valley Hall effect and optical selection rules in valleytronics. Furthermore, the emerging transition metal dichalcogenides (TMDs) materials naturally become the ideal candidates for valleytronics research attributable to their novel structural, photonic and electronic properties, especially the direct bandgap and broken inversion symmetry in the monolayer. However, the mechanism of inter-valley relaxation remains ambiguous and the complicated manipulation of valley predominantly incumbers the realization of valleytronic devices. In this review, we systematically demonstrate the fundamental properties and tuning strategies (optical, electrical, magnetic and mechanical tuning) of valley degree of freedom, summarize the recent progress of TMD-based valleytronic devices. We also highlight the conclusion of present challenges as well as the perspective on the further investigations in valleytronics.

Ye K., Liu L., Liu Y., Nie A., Zhai K., Xiang J., Wang B., Wen F., Mu C., Zhao Z., Gong Y., Liu Z., Tian Y.

Gant P., Huang P., Pérez de Lara D., Guo D., Frisenda R., Castellanos-Gomez A.

Strain engineering, which aims to tune the bandgap of a semiconductor by the application of strain, has emerged as an interesting way to control the electrical and optical properties of two-dimensional (2D) materials. Apart from the changes in the intrinsic properties of 2D materials, the application of strain can be also used to modify the characteristics of devices based on them. In this work, we study flexible and transparent photodetectors based on single-layer MoS2 under the application of biaxial strain. We find that by controlling the level of strain, we can tune the photoresponsivity (by 2-3 orders of magnitude), the response time (from

Kang M., Kim S., Jeon I., Lim Y.R., Park C., Song W., Lee S.S., Lim J., An K., Myung S.

Two-dimensional transition metal dichalcogenides (TMDs) such as molybdenum disulfide, have recently attracted attention for their applicability as building blocks for fabricating advanced functional materials.

Kwak J.Y.

A simple, non-destructive, and convenient method using Raman spectroscopy and Atomic Force Microscopy for extracting the absorption coefficient of MoS2 is presented. The attenuation of the substrate Raman signal intensity due to the MoS2 overlayer is found to be dependent on the MoS2 film thickness estimated from the AFM measurements. Using the light attenuation model from the measurements, the experimentally extracted absorption coefficient of the thin MoS2 flakes is determined to be 2.8 × 106 cm−1. This simple technique is capable of estimating the absorption coefficient of other two-dimensional layered materials.

Gonzalez Marin J.F., Unuchek D., Watanabe K., Taniguchi T., Kis A.

In recent years, two-dimensional materials have risen as an attractive platform for integrated optoelectronics, due to their atomic scale thickness, favorable electrical, mechanical, and optical properties. In particular, graphene has been exploited as an ultrafast light modulator and photodetector, operating at telecommunication wavelengths. However, materials with larger bandgaps are required for light detection in the visible range of the spectrum, with wide applications in space communication, industrial quality controls, light sensing, etc. Even though TMDC-based light emitting and detecting devices in the visible spectrum have already been realized, efficient light absorption and photocurrent generation on integrated devices has not been achieved yet. Here, we demonstrate the integration of an ultrasensitive MoS2 photodetector with a silicon nitride photonic circuit. In contrast to the limited vertical light absorption, we observe near-unity lateral absorption, which results in even higher responsivity. By fabricating an alternative device where the MoS2 semiconducting channel is combined with a hexagonal boron nitride (h-BN) substrate, we significantly improve the speed of the photodetector. Low power operation is further achieved in a third device with graphene local gates. These results pave the way for future TMDC-based integrated optoelectronic devices.

Zhang X., Tseng S., Lu M.

Two-dimensional (2D) MoS2 has recently become of interest for applications in broad range photodetection due to their tunable bandgap. In order to develop 2D MoS2 photodetectors with ultrafast response and high responsivity, up-scalable techniques for realizing controlled p-type doping in MoS2 is necessary. In this paper, we demonstrate a p-type multilayer MoS2 photodetector with selective-area doping using CHF3 plasma treatment. Microscopic and spectroscopic characterization techniques, including atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), are used to investigate the morphological and electrical modification of the p-type doped MoS2 surface after CHF3 plasma treatment. Back-gated p-type MoS2 field-effect transistors (FETs) are fabricated with an on/off current ratio in the order of 103 and a field-effect mobility of 65.2 cm2V−1s−1. They exhibit gate-modulated ultraviolet photodetection with a rapid response time of 37 ms. This study provides a promising approach for the development of mild plasma-doped MoS2 as a 2D material in post-silicon electronic and optoelectronic device applications.

Shin G.H., Park J., Lee K.J., Lee G., Jeon H.B., Choi Y., Yu K., Choi S.

In this study, we propose the fabrication of a photodetector based on the heterostructure of p-type Si and n-type MoS2. Mechanically exfoliated MoS2 flakes are transferred onto a Si layer; the resulting Si-MoS2 p-n photodiode shows excellent performance with a responsivity ( R) and detectivity ( D*) of 76.1 A/W and 1012 Jones, respectively. In addition, the effect of the thickness of the depletion layer of the Si-MoS2 heterojunction on performance is investigated using the depletion layer model; based on the obtained results, we optimize the photoresponse of the device by varying the MoS2 thickness. Furthermore, low-frequency noise measurement is performed for the fabricated devices. The optimized device shows a low noise equivalent power (NEP) of 7.82 × 10-15 W Hz-1/2. Therefore, our proposed device could be utilized for various optoelectronic devices for low-light detection.

Nardi M.V., Timpel M., Ligorio G., Zorn Morales N., Chiappini A., Toccoli T., Verucchi R., Ceccato R., Pasquali L., List-Kratochvil E.J., Quaranta A., Dirè S.

Transition metal dichalcogenides, such as molybdenum disulfide (MoS2), show peculiar chemical/physical properties that enable their use in applications ranging from micro- and nano-optoelectronics to surface catalysis, gas and light detection, and energy harvesting/production. One main limitation to fully harness the potential of MoS2 is given by the lack of scalable and low environmental impact synthesis of MoS2 films with high uniformity, hence setting a significant challenge for industrial applications. In this work, we develop a versatile and scalable sol-gel-derived MoS2 film fabrication by spin coating deposition of an aqueous sol on different technologically relevant, flexible substrates with annealing at low temperatures (300 °C) and without the need of sulfurization and/or supply of hydrogen as compared to cutting-edge techniques. The electronic and physical properties of the MoS2 thin films were extensively investigated by means of surface spectroscopy and structural characterization techniques. Spatially homogenous nanocrystalline 2H-MoS2 thin films were obtained exhibiting high chemical purity and excellent electronic properties such as an energy band gap of 1.35 eV in agreement with the 2H phase of the MoS2, and a density of states that corresponds to the n-type character expected for high-quality 2H-MoS2. The potential use of sol-gel-grown MoS2 as the candidate material for electronic applications was tested via electrical characterization and demonstrated via the reversible switching in resistivity typical for memristors with a measured ON-OFF ratio ≥102. The obtained results highlight that the novel low-cost fabrication method has a great potential to promote the use of high-quality MoS2 in technological and industrial-relevant scalable applications.

Huo N., Konstantatos G.

Conventional semiconductors such as silicon- and indium gallium arsenide (InGaAs)-based photodetectors have encountered a bottleneck in modern electronics and photonics in terms of spectral coverage, low resolution, nontransparency, nonflexibility, and complementary metal-oxide-semiconductor (CMOS) incompatibility. New emerging two-dimensional (2D) materials such as graphene, transition metal dichalcogenides (TMDs), and their hybrid systems thereof, however, can circumvent all these issues benefitting from mechanically flexibility, extraordinary electronic and optical properties, as well as wafer-scale production and integration. Heterojunction-based photodiodes based on 2D materials offer ultrafast and broadband response from the visible to far-infrared range. Phototransistors based on 2D hybrid systems combined with other material platforms such as quantum dots, perovskites, organic materials, or plasmonic nanostructures yield ultrasensitive and broadband light-detection capabilities. Notably the facile integration of 2D photodetectors on silicon photonics or CMOS platforms paves the way toward high-performance, low-cost, broadband sensing and imaging modalities.

Kumar R., Goel N., Raliya R., Biswas P., Kumar M.

2D materials are a promising new class of materials for next generation optoelectronic devices owing to their appealing optical and electrical properties. Pristine molybdenum disulfide (MoS2) is widely used in next generation photovoltaic and optoelectronic devices, but its low photo-dark current ratio prevents its use in highly efficient photo detection applications. Here, we decorated crumpled reduced graphene oxide (rGO) particles on a large-area vertically aligned MoS2 flake network to enhance the performance of the MoS2-based photodetector by forming multiple nanoscale p-n heterojunctions. The rGO/MoS2 device exhibited a significantly improved photoresponsivity of ∼2.10 A W-1 along with a good detectivity of ∼5 × 1011 Jones (Jones = cm Hz1/2/W) compared to that of the pristine MoS2 photodetector in ambient atmosphere. Moreover, the rGO/MoS2 photodetector showed a fast response of ∼18 ms with excellent stability and reproducibility in ambient air even after three months. The high performance of the photodetector is attributed to enhanced photoexcited carrier density and suppressed photo generated electron-hole recombination due to the strong local built-in electric field developed at the rGO/MoS2 interface. Our results showed that integration of rGO with MoS2 provides an efficient platform for photo detection applications.

He J., Yang Y., He Y., Ge C., Zhao Y., Gao L., Tang J.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have been widely used in electronic and optoelectronic devices. However, 2D TMDs suffer from surface defects and ambient gas absorption, which significantly degrade their electronic and optoelectronic properties. Here we revealed the passivation effect of methylamine (MA) halide on molybdenum disulfide (MoS2) in the outstanding lead-based/MoS2 hybrid structure. Lead-free MA3Bi2Br9 with a high-crystalline quasi-layered structure was used to prolong the MABr passivation effect on MoS2. As a result, MA3Bi2Br9-coated MoS2 photodetector achieved the fastest response time of 0.3 ms and the highest detectivity of 3.8 × 1012 Jones among the reported MoS2-based photodetectors so far. This photodetector also showed high photoresponse stability.

Zhou J., Qin L., Fang L., Zhu X., Wang L., Zhuang Z.

Kumar R., Shringi A.K., Wood H.J., Asuo I.M., Oturak S., Sanchez D.E., Sharma T.S., Chaurasiya R., Mishra A., Choi W.M., Doumon N.Y., Dabo I., Terrones M., Yan F.

Esposito F., Bosi M., Attolini G., Golovynskyi S., Seravalli L.

Two-dimensional molybdenum disulfide (MoS2) has garnered significant interest in optoelectronics due to its direct band gap, tunable optical properties and the potential for realizing the van der Waals heterostructures. This article provides a comprehensive overview of 2D MoS2 and its applications in photonics. We begin by discussing recent advancements in the bottom-up synthesis of MoS2 using chemical vapor deposition, focusing on novel approaches using liquid molybdenum precursors. Then, we review the latest developments in light-based devices leveraging MoS2, including light-emitting diodes, photodetectors, waveguides, optical cavities and single-photon sources. By summarizing recent achievements, this review provides insights into the prospects offered by MoS2 in photonics.

Mousavi Khaleghi S.S., Wei J., Liu Y., Wang Y., Fan Z., Li K., Chen J., Kudrawiec R., Yang R., Crozier K.B., Dan Y.

Zhu H., Wen Z., Xiong W., Wei X., Wang Z.

Zhang Z., Lei B., Tan Y., Zhang W., Fan Y., Kalimuthu R., Bhat A.A., Yang Y., Xu S., Zhang H., Wei Q., Gao S., Bi W., Feng J.

Mishra K., Chauhan R.K., Mishra R., Srivastava V.

Photodetectors are optoelectronic devices that can convert optical signals into electrical signals by way of the photoelectric effect. A model of CsSn0.5Ge0.5I3-based nip perovskite photodetector (PePd) with graphene oxide as electron transport material and carbazole unit with naphthalene is used as hole transport material is established. The device configuration was analysed using Solar Cell Capacitance Simulator-1 dimensional. The effects of absorber thickness, defect density of CsSn0.5Ge0.5I3, metal work function and operating temperature on device architecture have been investigated. For the incident light between 800 and 820 nm, a maximum responsivity and detectivity of 0.65 A/W and 3.6 × 1013 Jones are obtained, respectively. The proposed photodetector demonstrates broad-spectrum detection, covering both the visible and near-infrared (NIR) regions. These findings highlight CsGe0.5Sn0.5I3 and Cz-N as promising alternatives to conventional photodetector materials like InGaAs, Si-Ge, GaN and ZnO. These simulation results will assist in future research on high-performance lead-free PePd.

Chan C., Chan F., Chiu S., Chen L., Yu W., Hsieh C., Yang C.

This study aims to elucidate the specific Moiré correlation and associated exciton properties within MoS2 monolayers grown randomly oriented on a c-cut single-crystalline sapphire (Al2O3) substrate, which facilitates a distinct Moiré correlation.

Taherkhani A., Mohammadkhani R.

Sianturi I.S., Hadju A., Hidayatullah K., Ofiyen C., Mahardhika M.K., Supu I., Darma Y.

Abdul-Redaa H.M., Khashan K.S., Hadi A.A., Ismail R.A.

In this study, we used a one-step laser ablation method to combine In2O3 colloidal nanoparticles with multi-walled carbon nanotubes (MWCNTs) to create an In2O3 NPs-MWCNTs heterostructure for photodetectors. X-Ray Diffraction (XRD) analysis of the prepared samples revealed that the In2O3 NPs/MWCNTs nanostructure contained graphite peak at the (002) plane and In2O3 NPs crystalline peaks which are indexed to body-centred cubic phase. Transmission electron microscope (TEM) investigation revealed that In2O3 nanoparticles have a spherical shape nanoparticle with an average size of 20 nm, and 33 nm for In2O3 NPs -MWCNTs nanostructure. UV–Vis test showed that the optical energy gap of the In2O3 NPs decreased from 3.2 to 2.7 eV after incorporating CNTs. The I–V characteristics for the In2O3 NPs/Si and In2O3 NPs-decorated MWCNTs/Si photodetector were investigated under both dark and illumination cases. The responsivity of the In2O3 NPs/Si photodetector showed an increase from 0.43 to 1.15 A/W after introducing CNTs at a wavelength of 450 nm. The fabricated photodetector showed a high sensitivity for Vis–NIR detection. The limit detection of In2O3 NPs -MWCNTs/Si photodetector was determined to be 3.39 × 1011 Jones at 450 nm.

Patil K., Barve K., Pisal A., Ogale S., Bhave T.

AbstractFlexible photodetectors (FPDs) are emerging as essential components for next‐generation wearable optoelectronic devices, bendable imaging sensors, and implantable optoelectronics. However, the development of high‐performance FPDs hinges on the identification of innovative material systems that combine excellent optoelectronic properties, efficient charge transport, and scalable processing techniques. In this study, these challenges by introducing a novel hybrid paper‐based photodetector featuring a 2D MoS₂/N‐doped Graphene Quantum Dot (N‐GQD)/CsPbBr₃ quantum dot triple junction are addressed. This architecture is fabricated entirely through cost‐effective and easily scalable solution‐based methods, emphasizing the practicality of large‐scale production. The incorporation of N‐GQDs as an intermediate layer between MoS₂ nanoflowers and CsPbBr₃ QDs significantly enhances carrier transport and separation, leading to outstanding device performance. The materials and fabricated device are characterized by X‐ray diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy, UV–vis and Photoluminescence spectroscopy, and Ultra Violet photoelectron spectroscopy. The photodetector exhibits a remarkable responsivity of 0.458 A W−1 and a specific detectivity of 3.28 × 10¹¹ Jones, highlighting its potential for high‐sensitivity applications. These results underscore the originality of the triple‐junction design and its significance as a versatile, economical platform for advancing flexible and large‐area photodetectors, paving the way for their deployment in wearable optoelectronics and expanded photo communication technologies.

Engdahl J.N., Scammell H.D., Efimkin D.K., Sushkov O.P.

Rouhi H.F., Yıldırım F., Mahmoudi Chenari H., Biber M., Aydoğan Ş.

Rituraj, Yu Z.G., Kandegedara R.M., Fan S., Krishnamurthy S.

Photonic quantum technologies such as effective quantum communication require room temperature (RT) operating single- or few-photon sensors with high external quantum efficiency (EQE) at 1550 nm wavelength. The leading class of devices in this segment is avalanche photodetectors operating particularly in the Geiger mode. However, for superior performance, a trade-off has to be made between temperature of operation, device thickness, and EQE. Two-dimensional (2D) materials can be used to reduce the absorber thickness and thus dark current, leading to an increase in the operating temperature, but they suffer from low EQE. We use specifically stacked bilayer hexagonal BAs, with material properties calculated from first principles, on a co-optimized dielectric photonic crystal substrate to simultaneously decrease the dark current by three orders of magnitude at RT and maintain an EQE of >99%. The device can potentially be used in avalanche mode and hence can form a basis for single photon detection.