Near-infrared Photodetectors Research Articles

Demonstration of a low power and high-speed graphene/silicon heterojunction near-infrared photodetector

By introducing a Si well isolated structure into the graphene/Si heterojunction near-infrared photodetector, an operation speed more than 100 times faster was achieved.

Engineering Band Gap of Ternary Ag2TexS1−x Quantum Dots for Solution-Processed Near-Infrared Photodetectors

Silver-based chalcogenide semiconductors exhibit low toxicity and near-infrared optical properties and are therefore extensively employed in the field of solar cells, photodetectors, and biological probes. Here, we report a facile mixture precursor hot-injection colloidal route to prepare Ag2TexS1−x ternary quantum dots (QDs) with tunable photoluminescence (PL) emissions from 950 nm to 1600 nm via alloying band gap engineering. As a proof-of-concept application, the Ag2TexS1−x QDs-based near-infrared photodetector (PD) was fabricated via solution-processes to explore their photoelectric properties. The ICP-OES results reveal the relationship between the compositions of the precursor and the samples, which is consistent with Vegard’s equation. Alloying broadened the absorption spectrum and narrowed the band gap of the Ag2S QDs. The UPS results demonstrate the energy band alignment of the Ag2Te0.53S0.47 QDs. The solution-processed Ag2TexS1−x QD-based PD exhibited a photoresponse to 1350 nm illumination. With an applied voltage of 0.5 V, the specific detectivity is 0.91 × 1010 Jones and the responsivity is 0.48 mA/W. The PD maintained a stable response under multiple optical switching cycles, with a rise time of 2.11 s and a fall time of 1.04 s, which indicate excellent optoelectronic performance.

Self-Powered and Broadband Photodetectors Based on High-performance Mixed Dimensional Sb2O3/PdTe2/Si Heterojunction for Multiplex Environmental Monitoring.

Solar-blind ultraviolet (SBUV) to near-infrared (NIR) broadband photodetectors (BB-PD) have important applications in environmental monitoring and other applications. However, it is challenging to prepare SBUV-IR photosensitive materials via simple steps and to construct SBUV-IR broadband devices for multiplex detection with high sensitivity at different wavelengths. Here, self-powered and broadband photodetectors using a high-performance mixed dimensional Sb2O3 nanorod 1-dimension (1D)/monodisperse microdiamond-like PdTe2 3-dimension (3D)/Si (3D) heterojunction for multiplex detection of environmental pollutants with high sensitivity at broadband wavelength are developed. The 1D/3D mixed dimensional Sb2O3/PdTe2/Si structure combines the advantages of strong light absorption, high carrier transport efficiency of 1D Sb2O3 nanorods, and expansion of interface barrier caused by 3D microdiamond-like PdTe2 interlayer to improve the photocurrent density and self-powered ability. The efficient photogenerated charge separation enables anon/off ratio of more than 5×106. The device exhibits excellent photoelectric properties from 255 to 980nm with the responsivity from 4.56×10-2 to 6.55×10-1AW-1, the detectivity from 2.36×1012 to 3.39×1013Jones, and the sensitivity from 3.90×107 to 1.10×1010cm2W-1 without external bias. Finally, the proposed device is applied for the multiplex monitoring of environmental pollution gases NO2 with the detection limit of 200ppb and PM2.5 particles at mild pollution at broadband wavelength. The proposed BB-PD has great potential for multiplex detection of environmental pollutants and other analytes at broadband wavelength.

Self-powered polarization-sensitive photodetection and imaging based on Sb[formula omitted]Se[formula omitted] microbelt/Si van der Waals heterojunction with MXene transmittance window

Polarization-sensitive detection and imaging have many significant applications in target recognition, optical switches, industrial inspection, and so on. Herein, on-chip near-infrared photodetectors based on individual Sb2Se3 microbelt/Si van der Waals heterojunction with MXene transmittance window were designed. The fabricated Sb2Se3 microbelt/Si photodetector displays a broad spectral response that spans the visible to near-infrared light regions, as well as a peak photoresponse at a wavelength of 1000 nm. The optimized Sb2Se3 microbelt/Si photodetector exhibits excellent photovoltaic performance with an ultralow dark current of 10 pA, a high responsivity of 25 mA/W, a favorable detectivity of 1010 Jones, a fast response time of 1.7 ms/2.9 ms under near-infrared illumination with power density of 0.1 mW/cm2. The identified performance can be attributed to the heterojunction’s type-II band configuration, making it suited for the quick separation of photo-generated carriers. More importantly, polarization-sensitive photodetectors with an anisotropy ratio of 1.21 to 1.28 under the illumination of 940 nm light can be achieved. The Sb2Se3 microbelt/Si photodetector also demonstrates high-resolution single-pixel polarimetric imaging at zero bias. This work demonstrates an effective strategy for using anisotropic/isotropic Sb2Se3 microbelt/Si van der Waals heterojunction to realize high-performance, self-powered, and polarization-sensitive detection and imaging.

Implementing high-performance near-infrared photomultiplication-type organic photodetectors by synergistic effects of energetic disorder and charge tunneling injection

A high efficiency near-infrared (NIR) photomultiplication-type organic photodetector (PM-OPD) has been achieved by combining the energetic disorder and trap-assisted charge tunneling injection. The performance of the prepared NIR PM-OPD with simple structure was significantly improved, and the external quantum efficiency and specific detectivity (D*) reached 5675% and 5.0 × 1011 Jones, respectively. Furthermore, the high-performance NIR PM-OPD also showed application in human heart rate detection.

Fast Near-Infrared Photodetectors Based on Nontoxic and Solution-Processable AgBiS2.

Solution-processable near-infrared (NIR) photodetectors are urgently needed for a wide range of next-generation electronics, including sensors, optical communications and bioimaging. However, it is rare to find photodetectors with >300kHz cut-off frequencies, especially in the NIR region, and many of the emerging inorganic materials explored are comprised of toxic elements, such as lead. Herein, solution-processed AgBiS2 photodetectors with high cut-off frequencies under both white light (>1MHz) and NIR (approaching 500kHz) illumination are developed. These high cut-off frequencies are due to the short transit distances of charge-carriers in the ultrathin photoactive layer of AgBiS2 photodetectors, which arise from the strong light absorption of this material, such that film thicknesses well below 120nm are sufficient to absorb >65% of NIR to visible light. It is also revealed that ion migration plays a critical role in the photo-response speed of these devices, and its detrimental effects can be mitigated by finely tuning the thickness of the photoactive layer, which is important for achieving low dark current densities as well. These outstanding characteristics enable the realization of air-stable, real-time heartbeat sensors based on NIR AgBiS2 photodetectors, which strongly motivates their future integration in high-throughput systems.

Giant lateral photovoltaic effect in Ag/porous silicon/Si structure for high-performance near-infrared detection

The lateral photovoltaic effect demonstrates versatility across various applications, including photodetectors, imaging, spectroscopy, biosensing, and environmental monitoring. Challenges arise from the low energy of near-infrared photons, regarded as a bottleneck for high-sensitivity photodetector development in this spectrum, limiting applications like optical fiber communication and image sensors. However, this study achieved a remarkable 720.57 mV/mm sensitivity for the lateral photovoltaic effect in the near-infrared region with a 980 nm laser irradiation on an Ag/Porous Silicon/Si structure. This sensitivity surpasses previous observations several to hundreds of times and even outperforms many other structures in the short-wavelength spectrum, further emphasizing its significance in this field. The use of a unique fluoro-amino electrolysis technique ensures consistent porosity, mitigating the adverse effects of photoluminescence. Combined with surface Ag, it induces local surface plasmon resonance and efficient plasmon coupling, markedly increasing electron density. This highly sensitive structure propels advancements in near-infrared photodetectors and Raman signal enhancement, establishing a robust foundation for potential applications in highly sensitive photodetectors and biological sensors.

Near-infrared photodetector based on the surface modification of porous silicon with silver nanoparticles

This study describes the modification of Porous silicon (PS) by depositing commercial Ag powder on its surface and within its pores to improve its physical properties and performance as a near-infrared (NIR) photodetector. The incorporation of Ag-nanoparticles (Ag-NPs) into the PS structure increases the energy band gap from 1.74 eV to 2.46 eV and decreases the diffuse reflectance over a broad range of wavelengths. Afterward, NIR photodetectors of both structures are produced. The maximum current is measured at 850 nm for both photodetectors. In addition to a substantial decrease in the dark current of PS-Ag, PS-Ag's photo-excited current is 4.5 times greater than its dark current, whereas PS's photo-excited current is only 1.7 times greater. In addition, the I–V curves are used to determine the photodetector's sensitivity (S) and the current gain (G) at different incident light wavelengths. At wavelengths of 850 nm, the Au/PS-Ag/Au photodetector exhibits a greater sensitivity of 3.26 × 102 compared to the Au/PS/Au photodetector, which exhibits a sensitivity of 0.83 × 102. Based on the results, it is clear that modifying the PS with Ag-NPs is a strong candidate for excellent performance as a near-infrared photodetector in commercial photoelectronic device applications.

Highly sensitive fast-response near-infrared photodetectors based on triple cation Sn-Pb perovskite for pulse oximetry system

Highly sensitive fast-response near-infrared photodetectors based on triple cation Sn-Pb perovskite for pulse oximetry system

Towards cost-effective and lightweight surface plasmon resonance biosensing for H5N1 avian influenza virus detection: Integration of novel near-infrared organic photodetectors

H5N1 avian influenza virus (AIV) persists in causing highly fatal human infections, demanding rapid and accurate diagnostic assessment. In this study, we introduce an intensity-based SPR sensor utilizing NIR wavelength excitation in tandem with a specifically engineered NIR-OPD. The active layer of the OPD consists of a PTB7-Th and COTIC-4 F blend, offering an optimized response for a 980 nm excitation wavelength. Key performance metrics of this OPD include a low Jd of 0.185 nA/cm2, a high responsivity of 0.35 A/W, an EQE of 44.74%, and an exceptional detectivity of 4.59 × 1013 Jones at 980 nm wavelength under zero bias. It also exhibits a wide LDR of 113 dB. The integration of such OPDs into our SPR sensor provides advantages in compactness and cost-effectiveness. Employing this sensor, we detected the H5N1 AIV using a custom high-affinity polyclonal antibody against HA envelope of the H5N1 virus, completing analyses of culture medium samples within 12 min. The detection limit of this biosensor for the H5N1 AIV in PBS-diluted culture medium is approximately 4.3 × 104 copies/mL. When compared to a commercial H5-Ag lateral flow test kit, our biosensor showed a sensitivity 37 times higher. Key attributes of our biosensor include 3D printing technology for easy alignment of optical components and a rapid, simplified detection procedure. Collectively, our findings open up the potential of our SPR biosensor as an efficient tool for detecting H5N1 AIV, promising advancements in on-site detection methodologies.

Enhanced near-infrared photodetection via whispering gallery modes in the wave-shaped sidewall silicon nanopillar arrays.

We demonstrate a near-infrared (NIR) photodiode (PD) by using a wave-shaped sidewall silicon nanopillars (WS-SiNPs) structure. The designed WS sidewall nanostructure increases the horizontal component of incident light and induces multiple whispering-gallery modes with low-quality factor, which increases the light absorption path. Thus, the WS-SiNP PD shows improved spectral responsivity and external quantum efficiency over straight sidewall silicon nanopillars and planar PDs in the NIR region. Especially, the peak responsivity of 0.648 A/W is achieved at a wavelength of 905 nm, which is used for light detection and ranging. Comparison with commercial photodiodes demonstrates the good optoelectrical characteristics of the fabricated device. The improved characteristics are validated by 3D finite differential time domain simulations. Based on these results, our device shows the potential for cost-effective Si-based optoelectronic devices to be utilized in future advanced applications.

Polarization-Resolved Near-Infrared PdSe2 p-i-n Homojunction Photodetector.

Constructing high-quality homojunctions plays a pivotal role for the advancement of two-dimensional transition metal sulfide (TMDC) based optoelectronic devices. Here, a lateral PdSe2 p-i-n homojunction is constructed by electrostatic doping. Electrical measurements reveal that the homojunction diode exhibits a strong rectifying characteristic with a rectification ratio exceeding 104 and an ideality factor approaching 1. When functioning in photovoltaic mode, the device achieves a high responsivity of 1.1 A/W under 1064 nm illumination, with a specific detectivity of 1.3 × 1011 Jones and a high linearity of 45 dB. Benefiting from the lateral p-i-n structure, the junction capacitance is significantly reduced, and an ultrafast response (3/6 μs) is obtained. Additionally, the photodiode has the capability of polarization distinction due to the unique in-plane anisotropic structure of PdSe2, exhibiting a dichroic ratio of 1.6 at a 1064 nm wavelength. This high-performance polarization-sensitive near-infrared photodetector exhibits great potential in the next-generation optoelectronic applications.

Plasmonic-Enhanced Tunable Near-Infrared Photoresponse for Narrowband Organic Photodetectors.

Near-infrared (NIR) narrowband organic photodetectors (OPDs) can be essential building blocks for emerging applications including wireless optical communication and light detection, but further improvement of their performances remains to be a great challenge. Herein, a light manipulation strategy combining solution-processable gold nanorings (AuNRs)-based hole transporting layer (HTL) and an optical microcavity is proposed to achieve high-performance NIR narrowband OPDs. Optical microcavities with a Fabry-Pérot resonator structure, guided by theoretical simulation, are coupled with PM6:BTP-eC9-based OPDs to exhibit highly tunable NIR selectivity. The further integration of AuNRs array with NIR-customized localized surface plasmon resonance in the HTL of the NIR narrowband OPDs enables evident NIR absorption enhancement, yielding a specific detectivity exceeding 1013 Jones (1.5 × 1012 Jones, calculated from noise spectral density) at 820 nm, along with a finely selective photoresponse (full width at half-maximum of 80 nm) and a 3-fold increase in photocurrent intensity. Finally, the practical application of our OPDs is demonstrated in an NIR communication system. These results reveal the great potential of an appropriate optical design for developing highly performing NIR narrowband OPDs.

Tunable Contacts of Bi2 O2 Se Nanosheets MSM Photodetectors by Metal-Assisted Transfer Approach for Self-Powered Near-Infrared Photodetection.

Owing to the Fermi pinning effect arose in the metal electrodes deposition process, metal-semiconductor contact is always independent on the work function, which challenges the next-generation optoelectronic devices. In this work, a metal-assisted transfer approach is developed to transfer Bi2 O2 Se nanosheets onto the pre-deposited metal electrodes, benefiting to the tunable metal-semiconductor contact. The success in Bi2 O2 Se nanosheets transfer is contributed to the stronger van der Waals adhesion of metal electrodes than that of growth substrates. With the pre-deposited asymmetric electrodes, the self-powered near-infrared photodetectors are realized, demonstrating low dark current of 0.04 pA, high Ilight /Idark ratio of 380, fast rise and decay times of 4 and 6ms, respectively, under the illumination of 1310nm laser. By pre-depositing the metal electrodes on polyimide and glass, high-performance flexible and omnidirectional self-powered near-infrared photodetectors are achieved successfully. This study opens up new opportunities for low-dimensional semiconductors in next-generation high-performance optoelectronic devices.

High external quantum efficiency monolayer MoS2(1−x)Se2x phototransistor with alloying-induced near-infrared absorption

Due to intriguing electrical and optical properties, two-dimensional MoS2 has gained significant attention and emerged as a promising material in photonic and optoelectronic fields. Nevertheless, the intrinsic optical absorption of monolayer MoS2 is limited in the visible region only, restricting applications toward near-infrared (NIR) photodetection. Herein, we engineered the optical properties of MoS2 via alloying with Se to extend its optical absorption to the NIR region, and the phototransistor was fabricated based on monolayer MoS2(1−x)Se2x (x = ∼0.1). When under 780 nm (∼1.59 eV) illumination, the device delivered a photoresponsivity of 75.38 A/W, a specific detectivity of ∼1012 Jones, and an external quantum efficiency up to 11 230%. Additionally, it was revealed by density functional theory calculations that NIR absorption originated from the transition of valence states of sulfur vacancy (Vs) interband energy states between +1 and 0, providing an interband energy level of 1.58 eV away from the conduction band minima. Moreover, alloying of Se can suppress deep-level defects formed via Vs, further boosting device performance. This work has demonstrated high-performance NIR phototransistors based on ternary monolayer MoS2(1−x)Se2x, providing both a viable solution and fundamental mechanisms for NIR-blind MoS2 with extended optical absorption.

High Detectivity Near Infrared Organic Photodetectors Using an Asymmetric Non-Fullerene Acceptor for Optimal Nanomorphology and Suppressed Dark Current.

Recently, the development of non-fullerene acceptors (NFAs) for near-infrared (NIR) organic photodetectors (OPDs) has attracted great interest due to their excellent NIR light absorption properties. Herein, we developed NFAs by substituting an electron-donating moiety (branched alkoxy thiophene (BAT)) asymmetrically (YOR1) and symmetrically (YOR2) for the Y6 framework. YOR1 exhibited nanoscale phase separation in a film blended with PTB7-Th. Moreover, substituting the BAT unit effectively extended the absorption wavelengths of YOR1 over 1000 nm by efficient intramolecular charge transfer and extension of the conjugation length. Consequently, YOR1-OPD exhibited significantly reduced dark current and improved responsivity by simultaneously satisfying optimal nanomorphology and significant suppression of charge recombination, resulting in 1.98 × 1013 and 3.38 × 1012 Jones specific detectivity at 950 and 1000 nm, respectively. Moreover, we successfully demonstrated the application of YOR1-OPD in highly sensitive photoplethysmography sensors using NIR light. This study suggests a strategic approach for boosting the overall performance of NIR OPDs targeting a 1000 nm light signal using an all-in-one (optimal morphology, suppressed dark current, and extended NIR absorption wavelength) NFA.

High performance germanium on silicon photodiodes for back-end-of-line photonic integration

Integration of near-infrared photodetectors in the back-end-of-line requires low temperature growth of Ge (<450 °C). We have fabricated high performance, vertical incidence Ge-on-Si photodiodes under thermal budget constraints with as-grown diodes achieving an internal quantum efficiency (IQE) of 38% and a dark current density of Jd = 272 μA/cm2 at a reverse bias of Vr = 5 V and a wavelength of λ = 1310 nm. The photodiode design incorporates a remote heterointerface, demonstrating that Ge material quality is sufficiently high for minority carriers to diffuse to the Ge/Si interface. Post-growth annealing improves device performance, including 500 °C 3 h exposure that improves IQE to 57% and Jd = 165 μA/cm2. Low-temperature grown Ge-on-Si photodiodes give comparable performance to diodes processed at high temperatures despite thermal budget constraints.

Visible Light–Near-Infrared Photodetection on Cys-MoO3−x Nanoparticles for Photothermal Therapy against Papillary Thyroid Carcinoma

The excellent performance of semiconductor nanocrystals as sensitizers for photothermal therapy (PTT) has attracted the attention of many researchers; however, they are hindered by limited bandwidth and complex synthesis. To overcome these limitations, starting with an initial determination of photothermal conductivity, we synthesized and designed molybdenum and Cys-MoO3−x nanoparticles (NPs) for use in the minimally invasive treatment of papillary thyroid carcinoma (PTC), as the NPs are coated only with cysteine molecules. The obtained Cys-MoO2 NPs were used as a PTT reaction drug for topical application to PTC cells. The use of near-infrared photoconductive PTT in combination with low-toxicity biological chemotherapy reached a 90% efficacy for cancer treatment in vitro. The conducted experiments intuitively demonstrate that non-toxic Cys-MoO2 NPs are lethal to the cancer cells under visual (VL, 405 nm) and near-infrared (NIR, 808 nm) laser irradiation and can be precisely controlled. Therefore, this study provides a powerful, safe, and easily modified NP platform for photo-triggered PTC elimination with broad application prospects. Assessment of the ideal damage range indicates a high degree of controllability, allowing the tumor to be precisely targeted while minimizing damage to the surrounding healthy tissue. In conclusion, this study provides a convenient, safe, and powerful NP platform for the near-infrared photo-controlled PTT of PTC cells, which has broad application prospects for the elimination of PTC and other types of cancer.

A review on the role of nanotechnology in the development of near-infrared photodetectors: materials, performance metrics, and potential applications

A review on the role of nanotechnology in the development of near-infrared photodetectors: materials, performance metrics, and potential applications

Bulk Photovoltaic Effect in Chiral Layered Hybrid Perovskite Enables Highly Sensitive Near-Infrared Circular Polarization Photodetection

Bulk Photovoltaic Effect in Chiral Layered Hybrid Perovskite Enables Highly Sensitive Near-Infrared Circular Polarization Photodetection