Broadband Photodetector Research Articles

High-responsivity photodetectors made of indium selenide with visible to near-infrared photodetection

This study demonstrates indium selenide (InSe) photodetectors (PDs) with a broadband photodetection range from the visible to the near-infrared (NIR) region (400–1000 nm). The InSe flakes exfoliated from bulk material are transferred to a sapphire substrate, followed by the deposition of Ni/Au bi-layer metal contact to fabricate the metal-semiconductor–metal (M-S-M) PDs. In addition to an absorption edge at around 1000 nm, a strong absorption edge at around 516 nm is observed from the typical spectral response taken from the fabricated InSe M-S-M PDs. Under a bias voltage of -1 V, the typical responsivity at 400 nm is as high as 1130 A W-1, corresponding to a photoconductive gain of approximately 3500. Thus, InSe has potential application in broadband photodetection from the NIR to the visible region.

Planar Cation Passivation on Colloidal Quantum Dots Enables High-Performance 0.35-1.8µm Broadband TFT Imager.

Solution-processed colloidal quantum dots (CQDs) are promising candidates for broadband photodetectors from visible light to shortwave infrared (SWIR). However, large-size PbS CQDs sensitive to longer SWIR are mainly exposed with nonpolar (100) facets on the surface, which lack robust passivation strategies. Herein, an innovative passivation strategy that employs planar cation, is introduced to enable face-to-face coupling on (100) facets and strengthen halide passivation on (111) facets. The defect density of CQDs film (Eg ≈ 0.74eV) is reduced from 2.74×1015 to 1.04×1015 cm-3, coupled with 0.1eV reduction in the activation energy of defects. The resultant CQDs photodiodes exhibit a low dark current density of 14 nA cm-2 with a high external quantum efficiency (EQE) of 62%, achieving a linear dynamic range of 98dB, a -3dB bandwidth of 103kHz and a detectivity of 4.7×1011 Jones. The comprehensive performance of the CQDs photodiodes outperforms previously reported CQDs photodiodes operating at >1.6µm. By monolithically integrated with thin-film transistor (TFT) readout circuit, the broadband CQDs imager covering 0.35-1.8µm realizes the functions including silicon wafer perspectivity and material discrimination, showing its potential for wide range of applications.

Reduced Graphene Oxide/Se Microtube p–p Heterojunction for Self-Powered UV–NIR Broadband Photodetectors

Reduced Graphene Oxide/Se Microtube p–p Heterojunction for Self-Powered UV–NIR Broadband Photodetectors

High-performance broadband photodetector based on PtSe2/MoS2 heterojunction from visible to near-infrared region

High-performance broadband photodetector based on PtSe2/MoS2 heterojunction from visible to near-infrared region

Trap-assisted monolayer ReSe2/Si heterojunction with high photoconductive gain and self-driven broadband photodetector.

The development of photodetectors is crucial in fields such as optical communication, image sensing, medical devices and military equipment, where high sensitivity is paramount. We fabricated an ambipolar photodiode using monolayer triclinic ReSe2, synthesized by chemical vapor deposition on p-type Si substrate. The photodetector has a broadband response range from 405 to 1100 nm. The device exhibits high sensitivity to NIR radiation with a high Iph/Idark (ON/OFF) ratio of 5.8 × 104, responsivity (R) of 465 A/W, and specific detectivity (D) of 4.8 × 1013 Jones at open circuit voltage (Voc), indicating photovoltaic behavior. Our ReSe2/Si heterojunction photodetector also exhibits low dark current of 1.4 × 10-9 A and high external quantum efficiency (EQE) of 54368.2% for 1060 nm at -3 V, demonstrating a photoconductive gain. The maximum responsivity (R = 465 A/W) can be achieved at -3 V reverse bias under 1060 nm. The device has a high ideality factor (4.8) and power coefficient (α = 0.5), indicating the presence of interface and sub-gap states that enhance device responsivity at lower illumination intensities by re-exciting trapped carriers into the conduction band. Our results offer important insights into the underlying photo-physics of the ReSe2/Si heterojunction and propose promising avenues for developing advanced broadband photodetectors of high performance.

An A-D-A'-D-A-Type Narrow Bandgap Electron Acceptor Based on Selenophene-Flanked Diketopyrrolopyrrole for Sensitive Near-Infrared Photodetection.

Near-infrared organic photodetectors possess great application potential in night vision, optical communication, and image sensing, but their development is limited by the lack of narrow bandgap organic semiconductors. A-D-A'-D-A-type molecules, featuring multiple intramolecular charge transfer effects, offer a robust framework for achieving near-infrared light absorption. Herein, we report a novel A-D-A'-D-A-type narrow bandgap electron acceptor named DPPSe-4Cl, which incorporates a selenophene-flanked diketopyrrolopyrrole (Se-DPP) unit as its central A' component. This molecule demonstrates exceptional near-infrared absorption properties with an absorption onset reaching 1120 nm and a low optical bandgap of 1.11 eV, owing to the strong electron-withdrawing ability and quinoidal resonance effect induced by the Se-DPP unit. By implementing a doping compensation strategy assisted by Y6 to reduce the trap density in the photoactive layer, the optimized organic photodetector based on DPPSe-4Cl exhibited efficient spectral response and remarkable sensitivity in the range of 300-1100 nm. Particularly, a specific detectivity surpassing 1012 Jones in the wavelength range of 410-1030 nm is achieved. This work offers a promising approach for developing highly sensitive visible to near-infrared broadband photodetection technology using organic semiconductors.

Amorphous Gallium Oxide Nanosheets with Broad Absorption and Spin Polarization for Si‐Based UV‒Vis‒NIR Photodetectors

AbstractAchieving broad light absorption and high carrier separation efficiency is crucial for wide‐bandgap semiconductors to enable broadband photodetection applications. Here, amorphous gallium oxide nanosheets feature with broad absorption and spin polarization Wis synthesized, and assembled with graphene and p‐Si, realizing UV‒vis‒NIR photodetection. Extended X‐ray absorption fine structure reveals that a‐GaOx NSs possess lower tetrahedral Ga occupation (10%) compared to crystalline β‐Ga2O3 (50%). UV‒vis‒NIR diffuse reflectance spectra and magnetic hysteresis loops demonstrate broad absorption and weak ferromagnetism of a‐GaOx NSs, respectively. Density functional theory calculation further reveals sub‐gap states and spin polarization in a‐GaOx NSs. Moreover, combined with Mott–Schottky curves, photoluminescence and time‐resolved photoluminescence spectra inferred the effective suppression of carrier recombination via spin polarization of a‐GaOx NSs. The graphene/a‐GaOx NSs/p‐Si photodetector incorporates a back‐to‐back rectifying junction, acquiring a dark current as low as 63 pA. All photogenerated carriers are in the depletion region of the photodetector favouring efficient charge separation. This photodetector exhibits a response time of τrise<60 ms and τfall<120 ms, and high specific detectivity 1013 Jones over 254–1064 nm light.

Self-Powered Broadband Photodetectors Based on Large-Scale Continuous Films of Weyl Semimetal WTe2

Self-Powered Broadband Photodetectors Based on Large-Scale Continuous Films of Weyl Semimetal WTe₂

Bilayered Dion-Jacobson lead-iodine hybrid perovskite with aromatic spacer for broadband photodetection

Bilayered Dion-Jacobson lead-iodine hybrid perovskite with aromatic spacer for broadband photodetection

Low Temperature Synthesis of 2D p-Type α-In2Te3 with Fast and Broadband Photodetection.

2D compounds (A = Al, Ga, In, and B = S, Se, and Te) with intrinsic structural defects offer significant opportunities for high-performance and functional devices. However, obtaining 2D atomic-thin nanoplates with non-layered structure on SiO2/Si substrate at low temperatures is rare, which hinders the study of their properties and applications at atomic-thin thickness limits. In this study, the synthesis of ultrathin, non-layered α-In2Te3nanoplates is demonstrated using a BiOCl-assisted chemical vapor deposition method at a temperature below 350°C on SiO2/Si substrate. Comprehensive characterization results confirm the high-quality single crystal is the low-temperature cubic phase α-In2Te3 , possessing a noncentrosymmetric defected ZnS structure with good second harmonic generation. Moreover, α-In2Te3 is revealed to be a p-type semiconductor with a direct and narrow bandgap value of 0.76eV. The field effect transistor exhibits a high mobility of 18 cm2 V-1s-1,and the photodetector demonstrates stable photoswitching behavior within a broadband photoresponse from 405 to 1064nm, with a satisfactory response time of τrise = 1ms. Notably, the α-In2Te3 nanoplates exhibit good stability against ambient environments. Together, these findings establish α-In2Te3 nanoplates as promising candidates for next-generation high-performance photonics and electronics.

High-Performance Flexible Broadband Photoelectrochemical Photodetector Based on Molybdenum Telluride.

Flexible broadband photodetectors are desired but challenging to be fabricated for next-generation wearable intelligent optoelectronic devices. Considering the narrow bandgap and strong light absorption, molybdenum telluride (MoTe2) based photoelectrochemical photodetectors are successfully assembled by liquid phase exfoliation accompanied with the electrophoretic deposited method. This MoTe2-based photodetector shows a broadband detection in ultraviolet-near-infrared band, long-term stability within 18000s, and fast response in millisecond-level (response time≈19ms, recovery time≈26ms). More importantly, even though the MoTe2 photodetector is bent and twisted at a high degree for several hundred times, it still shows excellent flexibility with stable on-off switching characteristics. Additionally, this photodetector displays a good response for rotation angles in the range from 0° to 360°, and the extracted Iph maintain almost the same value approximately 0.97µAcm-2, suggesting an omnidirectional detection capability. This work demonstrates the proposed flexible photoanode shows a great potential in future broadband omnidirectional detection systems.

Broadband photodetector based on Co3O4/ZnO/Si double heterojunctions: A morphological and optoelectronic study

The growing demand for efficient and cost-effective optoelectronic devices has motivated extensive research into advanced photodetector architectures. This work realizes a robust platform for broadband photodetection via architectural engineering of Co3O4/ZnO/Si double heterojunctions using facile chemical spray pyrolysis. Comprehensive materials and device characterization provides fundamental insights into the role of tailored morphology, band alignment engineering, and defect landscape in dictating device behavior. Aligned ZnO nanorods and fine-grained Co3O4 layers enable efficient light harvesting and charge transport. A triple bandgap structure stemming from the synergistic combination of the two oxides facilitates broadband spectral response from 400 to 1000 nm. Based on the optical properties, triple energy bandgap ranges have been observed, ZnO exhibits an energy bandgap ranging from 2.35 eV to 3.15 eV, while Co3O4 shows energy bandgaps in the range of 1.85 eV–2.23 eV and 1.35 eV–1.5 eV. The responsivity measurements show that Co3O4/ZnO/Si double-heterojunction device has the highest responsivity over a wide range, with distinct peaks at 480 nm and 950 nm, reaching values of 3.5 A/W and 4.5 A/W, respectively. Analysis of electrical transport characteristics and energy band diagrams elucidates the photogenerated carrier dynamics and photocurrent generation governed by strategic heterointerfaces. These fundamental insights into nanoscale interface and architecture engineering lay the foundation for custom-designing high performance metal oxide heterojunction photodetectors through facile and scalable spray pyrolysis technique.

Surface plasmon resonance assisted donor–acceptor type covalent polymeric framework for hybrid photodetectors

In this paper, a surface plasmon resonance assisted hybrid photodetector (PD) made of a low bandgap covalent polymeric framework material is experimentally demonstrated. The PD demonstrated a broadband photodetection capability ranging between 350 and 1550 nm with subsecond transients. The fabricated hybrid PD offered a remarkable responsivity and external quantum efficiency of 42.87 A/W and 11 873% at 410 nm, respectively. The peak detectivity is recorded to be 7.43×1013 Jones at 400 nm. Up to 1550 nm, the hybrid PD offered a responsivity > 0.4 A/W, thereby showcasing its efficacy even for the near-infrared signals. The time-dependent photoresponse study estimated the rise time and fall time of the fabricated PD to be approximately 0.31 and 0.22 s, respectively.

High-Performance Flexible Broadband Photothermoelectric Photodetectors Based on Tellurium Films.

Mid- and far-infrared photodetectors that can operate at room temperature are essential for both civil and military applications. However, the widespread use of mid-to-far-infrared photonic technology faces challenges due to the need for low-temperature cooling of existing commercial semiconductors and the limited optical absorption efficiency of two-dimensional materials. We have utilized the photothermoelectric effect to fabricate a self-powered, broadband, and high-performance photodetector based on a one-dimensional tellurium nanorod array film. The device surpasses energy band gap limitations, functioning even at wavelengths up to approximately 10,600 nm. In particular, the detectivity of the device can reach 4.8 × 109 Jones at 4060 nm under room-temperature conditions, which is an order of magnitude higher than that of commercially available photodetectors. It demonstrates fast response and recovery times of 8.3 and 8.8 ms. Furthermore, the device demonstrates outstanding flexibility withstanding over 300 bending cycles and environmental stability. These results suggest a viable approach for designing and developing high-performance, room-temperature, wearable optoelectronic devices.

Cu2O@Au-CsPbI3 heterostructures for plasmon hot carrier transfer enhanced optoelectronics

Plasmon hot carrier devices have tremendous potential applications in broadband photovoltaics, photodetection, photocatalysis, and intelligent optoelectronics, as they have the ability to generate hot carriers with energy lower than the optical bandgap at Schottky junctions and broaden the spectral range. However, this is mostly challenged by the lack of effective methods for the separation, migration, and extraction of plasmon hot carrier. In this work, a Cu2O@Au-CsPbI3 heterostructure was fabricated using facile low-temperature solution synthesis and spin-coating technique. The proposed heterostructure benefits from the simultaneous transfer of plasmon hot holes to Cu2O and hot electrons to CsPbI3, as well as enhanced charge separation driven by the built-in electric field at the p-n heterojunction interface. The heterostructure realizes remarkably enhanced light absorption, reduces carrier recombination, and further improves conversion efficiency. It exhibits a wide spectrum response of ultraviolet-visible-near infrared and achieves enhanced photodetection performance. The results suggest that Cu2O@Au-CsPbI3 heterostructure is a promising candidate for optoelectronic devices based on the harvesting of plasmonic hot carriers.

P-type π-conjugated BTPDS-8 organic molecule for broadband hybrid photodetector with organic/inorganic heterostructure

A novel p-type π-conjugated organic small molecule 3,7-bis(4-([2,2′:6′,2''-terpyridin]−4′-yl)phenyl)− 5H-dibenzo[a,d][7]annulen-5-one (named as BTPDS-8) in which terpyridinyl units are linked to the dibenzosuberenone backbone by a phenyl bridge was successfully synthesized in four reaction steps. The synthesized organic material BTPDS-8 was fully characterized using 1H NMR, 13C NMR, IR, and HRMS spectroscopy techniques. Then, eleven BTPDS-8/Si heterojunctions were fabricated having non-linear current-voltage characteristics. Among these devices, the one with the highest rectification ratio (with 8.43 ×105) was analyzed in detail under UV and IR light as well as different intensities of visible light. Experimental results showed that the device has good photoresponse performance under any light source in addition to self-driven mode characteristics. It was observed that the saturation current and barrier height increased, and the ideality factor decreased, depending on the light intensity under visible light. Photocurrent, on/off ratio, responsivity, detectivity and NPDR were calculated from the optical measurements. The broad spectrum photoresponse of the BTPDS-8/Si heterojunction from UV to IR demonstrated that the device has the potential to be used as a broadband photodetector. The best performance was obtained under 850 nm IR light. The detectivity values under IR light were 1.22 × 1010 Jones and 7.53 × 109 Jones for V= 0.0 volts (self-driven mode) and V= −2.0 volts, respectively.

Development of ZnO and Si semiconductor-based ultraviolet photodetectors enhanced by laser-ablated silver nanoparticles

The present study employs a cost-effective laser ablation technique in combination with the RF sputtering method to successfully synthesize silver nanoparticles encapsulated by zinc oxide on a silicon (Si) substrate. This synthesis approach aims to enhance the efficiency of photodetector devices while concurrently reducing material expenses, thereby promoting advancements in photodetector applications. The incorporation of various plasmonic nanoparticles (NPs) into the photodetector's architecture is demonstrated as a means to substantially improve the photoresponse of UV photodetectors. Three distinct samples, denoted as AgNPs/Si, AgNPs/ZnO/Si, and ZnO/AgNPs/Si, underwent comprehensive analysis and characterization of their morphological attributes, crystal structures, elemental composition, and optical properties. The UV photodetection efficacy of these samples was evaluated by subjecting them to 385 nm UV light at different bias voltages. The current-voltage (I-V) characteristics of the ZnO/AgNPs/Si photodetector revealed significantly enhanced conductivity in comparison to the AgNPs/Si and AgNPs/ZnO/Si counterparts. Remarkably, the ZnO/AgNPs/Si photodetector exhibited the highest responsivity value of 132 A/W, accompanied by quantum efficiency of 429.88, sensitivity of 31,400%, gain of 315, detectivity of 18 × 1010 Jones, and a noise equivalent power (NEP) of 0.556 × 10–13 W. These findings underscore the efficacy of our innovative broadband photodetector, highlighting its potential for practical implementation. This research offers valuable insights into the enhancement of photodetector performance and its applicability in real-world scenarios.

Investigation of In2SexOy/In2Se3/Si dual-junction photodiode for self-powered broadband photodetection

We report a dual-junction strategy for fabricating a high-performance In2SexOy/In2Se3/Si heterojunction photodiode by oxidizing the epitaxial In2Se3 thin films. The device exhibits a suppressed dark current (4.2 × 10−11 A) and enhanced photocurrent at zero bias, benefiting from the double built-in electric fields. Consequently, it demonstrates excellent and uniform self-powered broadband (255–1050 nm) photodetection performance with the typical responsivity of several hundred mA/W, and detectivity of over 5 × 1011 Jones. Moreover, a fast response speed with a response time of 0.20 ms is achieved. Our investigation offers a potential route to construct full-spectrum photodetectors.

A Self-Powered Broadband Photodetector with High Photocurrent Based on Ferroelectric Thin Film Using Energy Band Structure Design

Self-powered photodetectors have the advantages of high sensitivity, sustainability, and small size and have become a research hotspot in advanced optoelectronic systems. However, the low output photocurrent density seriously hinders the practical application of ferroelectric self-powered photodetectors. Herein, the high-efficiency photoelectric detection performance of the Bi1-xHoxFeO3 ferroelectric self-powered photodetector is realized by doping Ho. The responsivity (R) and detectivity (D*) can reach 0.0159 A/W and 1.94 × 1011 Jones under monochromatic light with a wavelength of 900 nm. Meanwhile, the R and D* can reach 0.022 A/W and 2.65 × 1011 Jones under sunlight. These excellent photodetection performances are attributed to the high short-circuit current density (Jsc). When the Ho content is 6%, the output photocurrent reaches up to 0.81 mA/cm2. The systematic structure and photo-electric characteristic analysis suggest that the decrease in the band gap leads to the generation of a larger photocurrent while the ferroelectric polarization is reduced slightly. This work provides a new way to obtain high-performance self-powered photodetectors.

Controlled Synthesis of Large-Scale Uniform Bi2Se3 Thin Films for Self-Powered and Broadband Photodetection

Controlled Synthesis of Large-Scale Uniform Bi₂Se₃ Thin Films for Self-Powered and Broadband Photodetection