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Enhanced Photoresponse of Indium-Doped Tin Disulfide Nanosheets
摘要： Doping of tin disulfide (SnS2) is an effective strategy to regulate its physical and chemical properties. In this work, In doping was used to manipulate the photoresponse behavior of SnS2-based photodetectors. In-doped SnS2 nanosheets were synthesized via a facile hydrothermal method. It was found that the In doping concentration plays an important role in the size of the fabricated SnS2 nanosheets. With the increase in the In doping concentration, the lateral size of samples increased from ~210 to ~420 nm, but the crystallinity became poor at higher concentrations. EDX-mapping results show that the In was homogeneously distributed in the samples. In addition, a redshift was observed in the binding energy of Sn and S with the increased In doping concentration, which may be due to the p-type doping of In in SnS2. After In doping, the performance of SnS2-based photodetectors was significantly improved. The photoresponse speed of In-doped SnS2-based photodetectors was faster than pristine SnS2-based devices under the illumination of 532 and 405-nm lasers. This work develops an effective approach of In doping to enhance the photoresponse characteristics of SnS2-based photodetectors, and proves that In-doped SnS2 has vast potential in optoelectronic applications.
关键词： photoresponse characteristics,Doping,Tin disulfide,photodetector,Layered metal dichalcogenides
更新于2025-09-12 10:27:22
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Tellurene Photodetector with High Gain and Wide Bandwidth
摘要： Two-dimensional (2D) semiconductors have been extensively explored as a new class of materials with great potential. In particular, black phosphorus (BP) has been considered to be a strong candidate for applications such as high-performance infrared photodetectors. However, the scalability of BP thin film is still a challenge, and its poor stability in the air has hampered the progress of the commercialization of BP devices. Herein, we report the use of hydrothermal-synthesized and air-stable 2D tellurene nanoflakes for broadband and ultrasensitive photodetection. The tellurene nanoflakes show high hole mobilities up to 458 cm2/V·s at ambient conditions, and the tellurene photodetector presents peak extrinsic responsivity of 383 A/W, 19.2 mA/W, and 18.9 mA/W at 520 nm, 1.55 μm, and 3.39 μm light wavelength, respectively. Due to the photogating effect, high gains up to 1.9 ×103 and 3.15×104 are obtained at 520 nm and 3.39 μm wavelength, respectively. At the communication wavelength of 1.55μm, the tellurene photodetector exhibits an exceptionally high anisotropic behavior, and a large bandwidth of 37 MHz is obtained. The photodetection performance at different wavelength is further supported by the corresponding quantum molecular dynamics (QMD) simulations. Our approach has demonstrated the air-stable tellurene photodetectors that fully cover the short-wave infrared band with ultrafast photoresponse.
关键词： air-stable,two-dimensional (2D),wide bandwidth,tellurene,photodetector,high gain
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Self-Reference Optical Phase Demodulation using Narrow Absorption/Gain Peak
摘要： Detection (or demodulation) of the phase modulation is a critical operation in different photonic applications, in particular, in interferometric fiber sensors, material evaluation via laser induced ultrasound, coherent communications etc. Different techniques were proposed to overcome the main problem of conventional interferometers: necessity of stabilization of the quadrature operation point and compensation of the complex spatial structure of the detected wave. Here one can mention, active operation point stabilization via external opto-electronic loop [1], adaptive dynamic gratings based systems [2], self-reference (i.e. without external reference wave) confocal Fabry-Perot cavities [3], and configuration based on quantum phase memory of an ensemble of two-level atoms/molecules [4]. All these seemingly different approaches have the same common feature – they are based on utilization of a narrow absorption/gain spectral profile, artificial, as in the first two above-mentioned techniques, or natural, as in the two last cases. Here we analyse a general case of passing of the phase modulated wave through a narrow absorption/gain spectral line as a technique for its demodulation (i.e. its partial transformation into the intensity modulation wave) with the following detection by conventional photodetector.
关键词： photodetector,phase modulation,narrow absorption/gain spectral line,demodulation
更新于2025-09-12 10:27:22
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High-specific-detectivity, low-dark-current Ge nanowire metal-semiconductor-metal photodetectors fabricated by Ge condensation method
摘要： We have investigated Ge nanowire (NW) metal-semiconductor-metal (MSM) photodetectors with high specific detectivity and low dark current, in which various sizes Ge NWs were fabricated by three-dimensional (3D) Ge condensation techniques. It has been demonstrated that the photocurrent gain increases significantly from 6.31×104 to 4.47×106 with the reduction of Ge NW width from 170 to 35 nm. A low dark current of 5.1 nA and an ultra-high specific detectivity of 1.26×1014 cm·Hz1/2·W-1 at 560 nm under 0.51 V bias are achieved for the 35 nm wide Ge NW photodetector. It has been proposed that the interface states provided by SiGeOx formed during Ge condensation process serve as electron traps to generate photogating effect, resulting in high photocurrent gain and high specific detectivity in the MSM photodetector. The fully complementary metal-oxide-semiconductor (CMOS) compatible and scalable process suggests a great potential of the Ge NW for low cost, high performance near infrared photodetectors.
关键词： gain,Ge nanowire photodetector,Ge condensation technique,photogating effect
更新于2025-09-12 10:27:22
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Application of Quartz Tuning Fork in Photodetector Based on Photothermal Effect
摘要： A photodetector with a commercial quartz tuning fork (QTF) based on photothermal effect was demonstrated. Unlike the commonly used thermosensitive elements, a QTF with the mechanical resonance ability and the piezoelectric effect was used to amplify the photothermal signal. Operating at the optimal operating distance and modulation signal duty ratio selected for the photodetector, the photodetector achieved a good linear response at the wavelength of 1550 nm and 980 nm. And the photoresponsivity of the photodetector reach up to 515 mV/mW at the wavelength of 1550 nm. More important, the detection sensitivity of 0.75 pW at 203 s integration time has been achieved by using the Allan deviation analysis.
关键词： photothermal effect,Photodetector,quartz tuning fork
更新于2025-09-12 10:27:22
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Integrated color photodetectors in 40 nm standard CMOS technology
摘要： For the further integration of receivers in multi-color visible light communication systems, a novel color photodetector (PD) was designed and fabricated by using a 40 nm standard complementary metal oxide semiconductor (CMOS) process without any process modifications. The PD consists of CMOS photodiode and two-dimensional (2D) polysilicon subwavelength grating above the photodiode. The 2D polysilicon grating is controlled in structural parameters to realize color filtering, based on guided-mode resonance, for the first time in a standard CMOS process. Here three kinds of color PDs were designed to respond to the three primary colors. The measured results demonstrate that the color PDs exhibit wavelength selectivity in the visible range (400-700 nm) and the maximum peaks in the spectral response curves of them are at 660 nm (red), 585 nm (green) and 465 nm (blue), respectively. In addition, the added 2D polysilicon grating almost does not reduce the responsivity of the photodiodes.
关键词： two-dimensional polysilicon subwavelength grating,Color photodetector,visible light communication,complementary metal oxide semiconductor (CMOS)
更新于2025-09-12 10:27:22
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Variation of Optical Properties of Nitrogen-doped Graphene Quantum Dots with Short/Mid/Long-wave Ultraviolet for the Development of the UV Photodetector
摘要： Nitrogen-doped graphene quantum dots (NGQDs) synthesized from a single glucosamine precursor are utilized to develop a novel UV-photodetector. Optical properties of NGQDs can be altered with short (254 nm), mid (302 nm) and longwave (365 nm) UV (ultra-violet) exposure leading to the reduction of absorption from deep to mid UV (200 to 320 nm) and enhancement above 320 nm. Significant quenching of blue and near-IR fluorescence accompanied by the dramatic increase of green/yellow emission of UV-treated NGQDs can be used as a potential UV-sensing mechanism. These emission changes are attributed to the reduction of functional groups detected by Fourier transformed infrared spectroscopy, and free radical-driven polymerization of the NGQDs increasing their average size from 4.70 to 11.20 nm at 60 min treatment. Due to strong UV absorption and sensitivity to UV irradiation, NGQDs developed in this work are utilized to fabricate UV photodetectors. Tested under long/mid/short-wave UV, these devices show high photo-responsivity (up to 0.59 A/W) and excellent photo-detectivity (up to 1.03X1011 Jones) with highly characteristic wavelength-dependent reproducible response. This study suggests that the optical/structural properties of NGQDs can be controllably altered via different wavelength UV-treatment leading us to fabricate NGQD-based novel UV photodetectors providing high responsivity and detectivity.
关键词： UV photodetector,Optical Properties Modification,Short/mid/long-wave UV treatment,UV sensor,Nitrogen-doped graphene quantum dots
更新于2025-09-12 10:27:22
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[IEEE 2019 3rd International Conference on Circuits, System and Simulation (ICCSS) - Nanjing, China (2019.6.13-2019.6.15)] 2019 3rd International Conference on Circuits, System and Simulation (ICCSS) - Carbon Dots/Graphene Hybrids for UV Photodetectors
摘要： The intrinsical poor optical absorption and short carrier lifetime of graphene have restricted its practical application of photodetectors. Carbon dots (CDs) have received much attention due to their fascinating optical properties, environmentally-friendly nature, small size and superiority of a large optical absorptivity. Thus, in this work, hybrid photodetector of graphene and CDs has been proposed for the deep-UV photodetection, in which CDs integrated with graphene to form a planar hybrid structure. An inverse photo-electricity response was observed after illumination, which means the decline of conductivity under irradiation. The mechanism for this behavior is attributed to the built-in electric field generated across the interface between graphene layer and CDs layer, which separates the photogenerated electrons and holes, and promotes the holes to graphene layer and electrons to CDs layer. Our result demonstrates that the integration of graphene and CDs shows better optical absorption and wavelength selectivity. Together with the mechanism, it paves a step for practical applications of quantum dots sensitized graphene-based photodetectors.
关键词： heterostructure,carbon dots,photodetector,graphene
更新于2025-09-12 10:27:22
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3D Solar‐Blind Ga <sub/>2</sub> O <sub/>3</sub> Photodetector Array Realized Via Origami Method
摘要： A 3D solar-blind photodetector array is realized from amorphous Ga2O3 films grown on polyethylene terephthalate substrates via an origami route. The photodetector cells exhibit a dark current of 0.17 nA, and the peak responsivity is about 8.9 A W?1 at 250 nm with a quantum efficiency of 4450%. The photodetector shows a distinct cut-off wavelength at 268 nm with a solar-blind ratio of more than two orders of magnitude (photocurrent ratio between 250 nm/300 nm). The photodetector cells reveal excellent electrical stability after thousands of bending cycles. All the photodetector cells of the 3D photodetector array have a highly consistent performance. In addition, the device can execute the functions of capturing a real-time light trajectory and identifying multipoint light spatial distribution, which cannot be achieved in all the previously reported 2D solar-blind photodetectors. The results suggest new pathways to fabricate 3D photodetectors from conventional semiconductor films, which may find potential applications in optical positioning, tracking, imaging and communications, etc.
关键词： 3D photodetector,solar-blind photodetector,amorphous Ga2O3,origami
更新于2025-09-11 14:15:04
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Rhenium Diselenide (ReSe <sub/>2</sub> ) Near‐Infrared Photodetector: Performance Enhancement by Selective p‐Doping Technique
摘要： In this study, a near-infrared photodetector featuring a high photoresponsivity and a short photoresponse time is demonstrated, which is fabricated on rhenium diselenide (ReSe2) with a relatively narrow bandgap (0.9–1.0 eV) compared to conventional transition-metal dichalcogenides (TMDs). The excellent photo and temporal responses, which generally show a trade-off relation, are achieved simultaneously by applying a p-doping technique based on hydrochloric acid (HCl) to a selected ReSe2 region. Because the p-doping of ReSe2 originates from the charge transfer from un-ionized Cl molecules in the HCl to the ReSe2 surface, by adjusting the concentration of the HCl solution from 0.1 to 10 m, the doping concentration of the ReSe2 is controlled between 3.64 × 1010 and 3.61 × 1011 cm?2. Especially, the application of the selective HCl doping technique to the ReSe2 photodetector increases the photoresponsivity from 79.99 to 1.93 × 103 A W?1, and it also enhances the rise and decay times from 10.5 to 1.4 ms and from 291 to 3.1 ms, respectively, compared with the undoped ReSe2 device. The proposed selective p-doping technique and its fundamental analysis will provide a scientific foundation for implementing high-performance TMD-based electronic and optoelectronic devices.
关键词： photodetector,transition-metal dichalcogenides (TMDs),p-doping,selective doping,HCl doping,ReSe2,transistor
更新于2025-09-11 14:15:04