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Enhanced photoresponse of highly air-stable palladium diselenide by thickness engineering
摘要： Recently, palladium diselenide (PdSe2), with a unique low-symmetry puckered pentagon atomic morphology, has emerged as a promising candidate for next-generation nanoelectronics and optoelectronics because of its chemical stability and extraordinary electrical properties. Moreover, PdSe2 possesses a strong thickness-dependent bandgap that varies from 0 eV for bulk to 1.3 eV for monolayer, which can further render its potential applications in optoelectronics. However, the layer-dependent optoelectronic properties of PdSe2 are still lacking up to date. Herein, we studied the optoelectronics transport characteristics of high-quality PdSe2-based photodetectors with different thicknesses. We demonstrated an enhancement of PdSe2 photodetector performance owing to the band engineering via a thickness reduction. The highest responsivity of 5.35 A/W can be achieved with an external quantum efficiency of 1250% at the wavelength of 532 nm. We attribute such high performance in photoresponsivity to the high valley convergence in the conduction band of layered PdSe2, in agreement with first-principles calculation. Our results offer new insight into the layer-dependent optoelectronic properties of PdSe2 and open new avenues in engineering next-generation 2D-based electronics and optoelectronics.
关键词： photoresponsivity,palladium diselenide,photodetector,band convergence
更新于2025-09-16 10:30:52
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On the Choice of Metallic Contacts with Polycrystalline PbSe Films and Its Effect on Carrier Sweepout and Performance in Mid-wave Infrared (MWIR) Photodetectors
摘要： Carrier sweepout is one of the many phenomena that limit critical performance metrics of mid-wave infrared (MWIR) photodetectors, such as the photoconductive gain (c), photoresponsivity (g), specific detectivity (D*), and hence the overall performance of cameras built using these detectors. Preventing carrier sweepout in photoconductors at high applied bias and modulation frequencies can increase the electrical operating bias range and consequently expand the possible read-out integrated circuit design space and capabilities. Polycrystalline PbSe-based MWIR photodetectors have shown great potential for building integrated high-performance devices. We discuss herein the choice of metallic contacts for such detectors built by Northrop Grumman Systems Corp. under this program using the complex physics of carrier trapping and the interface of the contact metal with the photosensitive PbSe film that allows these detectors to be essentially free of carrier sweepout even at high applied electric fields.
关键词： band theory,photoresponsivity,PbSe,Mid-wave infrared detectors,carrier sweepout
更新于2025-09-12 10:27:22
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Highly Responsive Ultraviolet Sensor Based on ZnS Quantum Dot Solid with Enhanced Photocurrent
摘要： Detection of visible blind UV radiation is not only interesting but also of technologically important. Herein, we demonstrate the efficient detection of UV radiation by using cluster like ZnS quantum dot solid nanostructures prepared by simple reflux condensation technique. The short-chain ligand 3-mercaptopropionic acid (MPA) involved in the synthesis lead to the cluster like formation of ZnS quantum dots into solids upon prolonged synthesis conditions. The ZnS QD solid formation resulted in the strong delocalization of electronic wave function between the neighboring quantum dots. It increases the photocurrent value, which can be further confirmed by the decrease in the average lifetime values from 64 to 4.6 ns upon ZnS cluster like QD solid formation from ZnS QDs. The ZnS quantum dot solid based UV sensor shows good photocurrent response and a maximum responsivity of 0.31 (A/W) at a wavelength of 390 nm, is not only competitive when compared with previous reports but also better than ZnS and metal oxide-based photodetectors. The device exhibits a high current value under low-intensity UV light source and an on/off ratio of IUV/Idark = 413 at zero biasing voltage with a fast response. Further, photocurrent device has been constructed using ZnS quantum dot solid nanostructures with graphene hybrids as an active layer to improve the enhancement of photoresponsivity.
关键词： graphene hybrids,ZnS quantum dot solid,photoresponsivity,UV sensor,photocurrent
更新于2025-09-12 10:27:22
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Metamaterial grating-integrated graphene photodetector with broadband high responsivity
摘要： Graphene has some outstanding properties in the photoelectric field, especially ultra fast response and broad spectrum absorption, which have led to strong attraction on graphene photodetector. However, the photo-responsivity of pure graphene device is below 10 mA W?1. It would limit the application of graphene photodetector. Here, we design a metamaterial structure with a broadband high absorption spectrum. And by integrating it into the graphene photodetector, the high photoresponsivity of a pure graphene photodetector in a broadband range could be acquired. The photoresponsivity of photodetector can achieve nearly 200 mA W?1, which is two orders higher than the one of pure monolayer graphene photodetector. Besides, the photodetector also keeps the broadband photoresponse. The hot carriers can be generated by coupling of multiple resonances and effectively transported to graphene with the advantage of ultrathin metal film. Based on this work, more potential applications of graphene photodetector could be developed in some related fields.
关键词： Metamaterial,Graphene,Photodetector,Photoresponsivity
更新于2025-09-11 14:15:04
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[IEEE 2018 15th International Conference on Smart Cities: Improving Quality of Life Using ICT & IoT (HONET-ICT) - Islamabad, Pakistan (2018.10.8-2018.10.10)] 2018 15th International Conference on Smart Cities: Improving Quality of Life Using ICT & IoT (HONET-ICT) - Two Dimensional Materials based Heterostructures for Photosensing Applications
摘要： Graphene (Gr) and transition metal dichalcogenides (TMDC) have wide scope in electronic and optoelectronic incredible optical and electrical properties. The study investigates the utilization of molybdenum disulfide-graphene (MoS2-Gr) hybrid field effect transistor (FET) as photosensor. The photo-current response of hybrid FET was studied for source-drain voltages(Vds) range from 1 to 5 V. The important optical figure of merits such as photoresponsivity (R(cid:2)) and external quantum efficiency (EQE) are calculated to evaluate the performance of FET. Enhancement in the optical performance of FET is observed. MoS2-Gr divulges high R(cid:2) (3.34×103 AW-1) while the EQE of hybrid FET (1.8×104) is higher than that of individual structures. This methodology of fabricating TMDCs-Gr based hybrid devices opens new doors for advances in highly efficient photosensor for sensing and optoelectronic applications.
关键词： external quantum efficiency,photoresponsivity,Gaphene,hybrid structure,molybednum disulfide
更新于2025-09-09 09:28:46