Efficient Photodetectors Research Articles

Joule-heating induced phase transition in 1T-TaS2 near room temperature probed by thermal imaging of power dissipation

Electrically induced phase transition in 1T-TaS2 at room temperature has various applications, including efficient oscillators and broadband photodetectors. However, the physical mechanism behind the electrically induced phase transition is still not clear due to the lack of direct temperature measurements during the transition. To shed light on this problem, in this Letter, we directly image the spatially resolved temperature of a 1T-TaS2 device by IR thermal microscopy. Combining this method with pulsed electrical transport measurements, Raman spectroscopy, and a simple resistor network model, we show that the transition is a result of Joule-heating. More broadly, we show that thermal imaging is important to determine the power dissipation in electronic devices due to the inhomogeneous nature of the temperature distribution.

UV and Visible Photodetectors of MAPbBr3 and MAPbCl3 Perovskite Single Crystals via Single Photocarrier Transport Design

AbstractUnderstanding photogenerated charge transport is critical to further improving the performance of perovskite‐based devices. In this study, the low‐defect perovskite CH3NH3PbX3 (X = Br or Cl) single crystals, which are an ideal platform for high‐quality optoelectronic devices, are fabricated to examine characteristics of photodetectors with electrodes with Au or Ag, and interlayer of TiO2. The transport mechanism of the photogenerated carriers in each device is elucidated by analysis of the current density–voltage curves under dark or a 405 nm of super‐bandgap illumination or a 640 nm of sub‐bandgap illumination. The photocurrent under the 405 nm illumination is improved under the hole‐dominant Au‐device of p‐type bromide crystals and the electron‐dominant Ag‐device of n‐type chloride crystals. The defect‐assisted excitation under 640 nm illumination is associated with generation of the holes with the defects located near the conduction band or the electrons with the valence band in each perovskite materials. With this conception, the responsivity of 0.07 A W−1, specific detectivity over 1011 Jones, and external quantum efficiency around 16% are obtained in the best performing devices. The present results suggest a promising strategy for designing efficient photodetectors using photogenerated and trap‐assisted photocarriers that contribute to enhanced photocurrent.

Enhanced Surface Passivation by Atomic Layer-Deposited Al2O3 for Ultraviolet-Sensitive Silicon Photomultipliers

This article describes a superior passivation of p-type (p^&#x002B;) Si surface by an Al₂O₃ thin film that is synthesized by plasma-assisted atomic layer deposition (ALD) for ultraviolet-sensitive silicon photomultipliers (SiPMs), compared to conventional SiO₂ and SiN_<i>x</i> passivation schemes. The superiority of Al₂O₃ passivation is due not only to a sufficiently low interface defect density, but also to a high density of built-in negative charges. A 7-nm thin Al₂O₃ film can yield an emitter saturation current density of &#x007E;8 fA/cm² on a high sheet resistance p^&#x002B; layer, compared to &#x007E;60 and &#x007E;1480 fA/cm² for thermal SiO₂ and SiN_<i>x</i> passivation. This superior surface passivation allows the photon-generated carriers to have higher probabilities to reach the high-field region to trigger an avalanche event. In addition, the Al₂O₃ thin film provides very low values of effective surface recombination velocity on low resistivity n- and p-type Si surfaces, which can lead to well-passivated surface features on the guard ring and trench isolation regions of SiPM. These demonstrate the potential of the Al₂O₃ thin film passivation to improve the quantum efficiency and thus photo-detection efficiency (PDE) of ultraviolet-sensitive SiPM with p^&#x002B;/n^&#x2212;/n/n^&#x002B; structure.

Metasurface Colloidal Quantum Dot Photodetectors

Efficient photodetectors that can be easily engineered for a specific spectral window are of high interest. Here, we report on the design, fabrication, and characterization of metasurface-enhanced photodetectors and photodiodes using colloidal quantum dots. We fabricate photoconductors optimized for the wavelength range around 1550 nm featuring responsivities of up to 8000 A/W with low noise equivalent powers on the order of tens of pW/Hz. Further, we produce photodiodes with responsivities of ∼5 mA/W that offer faster responses (14 μs rise time). The high responsivities are due to the metasurface, which increases the absorption by a factor of 10 compared to that of a quantum dot thin film of the same thickness and a structure that enables a photo-gain. We introduce a metasurface to detect either of the two orthogonal polarizations. The fabricated photoconductors operate at low voltages (1–5 V), making them compatible with the complementary metal-oxide-semiconductor (CMOS) read-out circuitry.

Enhanced Photoresponse and Wavelength Selectivity by SILAR-Coated Quantum Dots on Two-Dimensional WSe2 Crystals.

High-performance photodetectors play crucial roles as an essential tool in many fields of science and technology, such as photonics, imaging, spectroscopy, and data communications. Demands for desired efficiency and low-cost new photodetectors through facile manufacturing methods have become a long-standing challenge. We used a simple successive ionic layer adsorption and reaction (SILAR) method to synthesize CdS, CdSe, and PbS nanoparticles directly grown on WSe2 crystalline flakes. In addition to the excellent wavelength selectivity for (30 nm) CdS, (30 nm) CdSe, and (6 nm) PbS/WSe2 heterostructures, the hybrid devices presented an efficient photodetector with a photoresponsivity of 48.72 A/W, a quantum efficiency of 71%, and a response time of 2.5–3.5 ms. Considering the energy band bending structure and numerical simulation data, the electric field distribution at interfaces and photocarrier generation/recombination rates have been studied. The introduced fabrication strategy is fully compatible with the semiconductor industry process, and it can be used as a novel method for fabricating wavelength-tunable and high-performance photodetectors toward innovative optoelectronic applications.

A Demystified Guide on Fabrication and Characterization of Perovskites‐Based Optoelectronic Devices

It is by no means an exaggeration that perovskites have been preeminent in championing revolution of energy‐harnessing and energy‐saving devices such as photodetectors and supercapacitors. In particular, huge and relentless research efforts are being channeled toward improving efficiency of perovskites‐based photodetectors. Some of these efforts may be categorized under material synthesis, device architecture, device fabrication, and device characterization. Herein, a guide to standard techniques of synthesizing perovskites materials is presented, fabricating photodetectors and characterizing photodetectors. The information in the present review is carefully synthesized from practices reported by authors of the most efficient photodetectors. Also, characterization techniques that leads to overestimation of figures of merits are highlighted to set benchmarks for validity of figures of merits obtained from photodetectors. Finally, tons of open research questions on material modification and device fabrication are identified in this review, setting up foundations for further improvement in performance of perovskites‐based photodetectors.

Acridine based metal-organic framework host-guest featuring efficient photoelectrochemical-type photodetector and white LED.

A novel metal-organic framework (MOF) host-guest material [Cd3(EtOIPA)4(HAD)2]·H2O has been successfully synthesized by the reaction of 5-ethoxyisophthalic acid (EtOIPA), acridine (AD) and Cd(II) salts under hydrothermal conditions. Structurally, the title MOF possesses a trinucleate Cd(II) based 2D double-layer with the protonated AD cations as the template encapsulated into the grids. The combination of experiments and theoretical calculations reveals that the orderly arrangement of EtOIPA dimers, protonated AD cations and trinucleate Cd(II) clusters generates highly delocalized π-electron channels with a prolonged exciton lifetime. The MOF powders show bright yellow emission with a long lifetime of 50.63 ns. Photoelectrochemical measurements reveal a high photocurrent density ratio of 290 between light and dark conditions at 0 V bias potential, making it a perfect self-driven photodetector. By coating the yellow phosphor on a commercially available blue LED, a high performance white LED with CIE, CCT and CRI values of (0.325, 0.336), 88.2 and 5844 K, respectively can be obtained.

Effective surface passivation of environment-friendly colloidal quantum dots for highly efficient near-infrared photodetectors

Eco-friendly CuInSnSe (CISnSe) QDs with broadband absorption were engineeredviaeffective ZnSe shell passivation to fabricate highly efficient near-infrared photodetectors.

Pulsed laser deposition for conformal growth of MoS2 on GaN nanorods for highly efficient self-powered photodetection

Enhanced photoresponsivity via conformal growth of MoS2 on GaN nanorods.

Mixed AgBiS2 nanocrystals for photovoltaics and photodetectors.

Heavy-metal-free colloidal nanocrystals are gaining due attention as low-cost, semiconducting materials for solution-processed optoelectronic applications. One common limitation of such materials is their limited carrier transport and trap-assisted recombination, which impede the performance of thick photoactive layers. Here we mix small-size and large-size AgBiS2 nanocrystals to judiciously favour the band alignment in photovoltaic and photodetector devices. The absorbing layer of these devices is fabricated in a gradient fashion in order to maximise charge transfer and transport. We implement this strategy to fabricate mixed AgBiS2 thin film solar cells with a power conversion of 7.3%, which significantly surpasses the performance of previously reported devices based on single-batch AgBiS2 nanocrystals. Additionally, this approach allows us to fabricate devices using thicker photoactive layers that show lower dark currents and external quantum efficiencies exceeding 40% over a broad bandwidth – covering the visible and near infrared range beyond 1 μm, thus unleashing the potential of colloidal AgBiS2 nanocrystals in photodetector applications.

Early Crystal Growth Suppression by Washing Solvent for Efficient Self-Powered Perovskite Photodetector

Early Crystal Growth Suppression by Washing Solvent for Efficient Self-Powered Perovskite Photodetector

Tailoring the interface assembly of mesoporous TiO2 on BTO film toward high-performance UV photodetectors

A heterojunction film consisting of BaTiO3@mesoporous TiO2 was engineered via an interface assembly strategy and spin-coating to fabricate a highly efficient UV photodetector.

A bilayered two-dimensional hybrid perovskite with a cage-templated secondary cation for high efficiency photodetection

A novel two-dimensional hybrid perovskite (IA)2(DMA)Pb2Br7 was obtained by introducing a large secondary cation DMA+ into the PbBr6 framework. A highly efficient array photodetector has been assembled using its crystal.

Study of Intrinsic Point Defects in Γ-In2se3 for the Realization of an Efficient Uv Photodetector

Study of Intrinsic Point Defects in Γ-In2se3 for the Realization of an Efficient Uv Photodetector

Poly-3-Methyl Aniline-Assisted Spherical PbS Quantum Dots through the Ionic Adsorption Deposition Method as a Novel and Highly Efficient Photodetector in UV, Vis, and NIR Regions

This study describes the preparation and characterization of glass/poly-3-methyl aniline (P3MA)/PbS quantum dot (QD) optoelectronic photodetector to detect and sense the light in broad spectral regions of UV, Vis, and NIR. This work is carried out to solve the drawbacks of other studs that prepare detectors in just one or two optical regions. Previous studies have used high-priced techniques. The deposition of P3MA on the glass surface was carried out by in situ oxidation process. Then, this polymer film was used to assist the deposition of PbS-QD particles through the ionic adsorption deposition method. The latter was performed using four different concentrations of Pb(NO3)2 solution (0.01, 0.03, 0.05, and 0.07 M) to form four P3MA/PbS composites: I, II, III, and IV, respectively. The chemical structure, morphologies, and electrical and optical properties of these composites were determined using different analytical tools. The SEM confirmed the formation of spherical QD particles of PbS on the P3MA surface. The TEM analysis showed that the composite has an average size of 5 nm, with the interatomic distances of 0.4 nm. Furthermore, the optical band gap values were 1.53, 1.52, 1.50, and 1.51 eV, respectively. The optoelectronic device could detect and sense light from 390 to 636 nm under various optical wavelengths. The produced current density ([Formula: see text]) values decreased from 0.029 mA.cm-2 at 390 nm to 0.022 mA.cm-2 at 500 nm and then increased until 0.024 mA.cm-2 at 636 nm. The light sensing was determined through the photoresponsivity ([Formula: see text]) and detectivity ([Formula: see text]) parameters, in which the photodetector has [Formula: see text] and [Formula: see text] values of 0.29 mA.cm-2 and [Formula: see text] Jones, respectively. Finally, a simple mechanism was proposed to explain the light sensing through the prepared optoelectronic device. Soon, our team works on the industrial applications of this optoelectronic device in the industry field related to the great optoelectronic device technical properties and its low cost and easy preparation.

A Super-Boosted Hybrid Plasmonic Upconversion Process for Photodetection at 1550nm Wavelength.

A super-boosted hybrid plasmonic upconversion (UC) architecture comprising a hierarchical plasmonic upconversion (HPU) film and a polymeric microlens array (MLA) film is proposed for efficient photodetection at a wavelength of 1550nm. Plasmonic metasurfaces and Au core-satellite nanoassembly (CSNA) films can strongly induce a more effective plasmonic effect by providing numerous hot spots in an intense local electromagnetic field up to wavelengths exceeding 1550nm. Hence, significant UC emission enhancement is realized via the amplified plasmonic coupling of an HPU film comprising an Au CSNA and UC nanoparticles. Furthermore, an MLA polymer film is synergistically coupled with the HPU film, thereby focusing the incident near-infrared light in the micrometer region, including the plasmonic nanostructure area. Consequently, the plasmonic effect super-boosted by microfocusing the incident light, significantly lowers the detectable power limit of a device, resulting in superior sensitivity and responsivity at weak excitation powers. Finally, a triple-cation perovskite-based photodetector coupled with the hybrid plasmonic UC film exhibits the excellent values of responsivity and detectivity of 9.80AW-1 and 8.22×1012 Jones at a weak power density of ≈0.03mWcm-2 , respectively, demonstrating that the device performance is enhanced by more than 104 magnitudes over a reference sample.

High-performance self-powered visible-blind ultraviolet photodetection achieved by ferroelectric PbZr0.52Ti0.48O3 thin films

Self-powered visible-blind ultraviolet (UV) photodetection has been generally achieved based on the built-in electric field formed within the complicated devices such as pn or Schottky junctions, which involves a complicated device fabrication process. In contrast, employing the ferroelectric materials featured with unique bulk photovoltaic effect as absorbers will simplify the device structure and the subsequent device fabrication process without losing the performance of self-powered photodetection. In the current work, the fabrication of high-performance self-powered visible-blind UV photodetectors based on ferroelectric PbZr0.52Ti0.48O3 (PZT) thin films has been reported. The results showed that the spin-coated PZT thin films exhibited superior ferroelectric properties. On this basis, an efficient, stable, and repeatable self-powered UV photodetection has been achieved in the Au/PZT/FTO (fluorine-doped tin oxide) structured devices with the responsivity and detectivity as high as 0.092 A/W and 1.2 × 1012 Jones, respectively. More interestingly, the self-powered photocurrent has been further enhanced when downward polarizing the PZT thin film. The results reported in this work highlight the superiorities of ferroelectric PZT-based self-powered visible-blind UV photodetectors and provide valuable strategies for the fabrication of high-performance self-powered photodetectors with a simplified device structure in the future.

Gate tunable photoresponse of a two-dimensional p-n junction for high performance broadband photodetector

Optoelectronic devices based on two-dimensional (2D) van der Waals (vdWs) materials and their heterostructures are promising owing to their intriguing properties. However, the achievement of high-performance photodetectors over a wide detection range is still limited. In particular, detection in the near-infrared (NIR) region has not been attained successfully because of the relatively low responsivity to date. Herein, we report an efficient photodetection from visible to NIR ranges using a ReS2/Te vdWs heterostructure. The dependence of the photocurrent on the incident power reveals that the dominant operating mechanism can be switched between the photogating effect and photoconductive effect by applying the back-gate voltage. The ReS2/Te photodetector exhibits remarkable responsivities of 3 × 106 A W‒1 at 458 nm and 1 × 106 A W‒1 at 1062 nm laser irradiations, and an ultrahigh photoconductive gain (up to ∼108) resulting from the strong photogating effect. These outstanding performances demonstrate that the ReS2/Te vdWs heterostructure is suitable for high-performance broadband photodetectors in practical applications.

Defects mediated optical emissions and efficient photodetection characteristics of sol–gel derived Ag-doped ZnO nanostructures for UV sensor

In the present work, defects mediated optical emission and efficient photodetection characteristics of ZnO:Ag (0, 2, 5, and 7 wt%) nanoparticles (NPs) synthesized by sol–gel method have been investigated for UV sensor. X-ray diffraction (XRD) patterns show the polycrystalline nature of ZnO NPs. The crystallite sizes corresponding to most intense peak (101) are found to be in the range of 10–20 nm. Effective enhancement of defect-mediated visible emissions is observed in Ag-doped ZnO NPs. Red-shift of UV peak in Ag-doped ZnO may be due the tensile strain upon Ag doping. Pure ZnO exhibits anomalous UV sensing, which is absent in ZnO NPs doped with Ag. The 7 wt% Ag-ZnO NPs is found to efficient UV photoresponsive. The results obtained by doping of Ag contents in the ZnO can be capable for making efficient and consistent prototype UV sensors.

Ferroelectric Materials for Solar Energy Scavenging and Photodetectors

AbstractThe photovoltaic devices based on ferroelectrics have drawn plenty of attention for providing a promising solar energy harvesting technology and efficient photodetectors. In this review, mainly the photoelectric properties of ferroelectric materials are introduced. First, three different types of ferroelectrics and primary representative materials are reviewed. Second, four existing principles and mechanisms of the photovoltaic effect in ferroelectrics are studied in great detail. Then, the typical design construction utilizing ferroelectrics for solar energy scavenging, photodetectors, and other photovoltaic device architectures is summarized. Lastly, the properties and characteristics of photovoltaic devices based on ferroelectrics are reviewed in the form of tables and the prospect of ferroelectric photovoltaic devices is discussed.