High-performance Photodetectors Research Articles

Fabrication of Sb2Se3-based high-performance self-powered Visible-NIR broadband photodetector

Fabrication of Sb2Se3-based high-performance self-powered Visible-NIR broadband photodetector

A nanoflower-like GaSe/β-Ga2O3 based heterostructure for highly efficient self-powered broadband photodetectors

The combination of GaSe nanoflowers with β-Ga2O3 results in a high-performance heterojunction photodetector with self-powered operation and outstanding responsivity from deep UV to visible wavelengths.

High-performance and self-powered visible light photodetector using multiple coupled synergetic effects.

In this work, we demonstrate, for the first time, that coupling together the pyroelectric effect, the photovoltaic effect and the plasmonic effect is a novel method to significantly enhance the performance of self-powered photodetectors in the visible region. Photodetectors based on tri-layered heterojunction of n-Si/p-SnO/n-ZnO through the inclusion of silver (Ag) nanoparticles (NPs) at the SnO/ZnO interface were fabricated. The photo-response of the device, with excitation from a chopped 650 nm wavelength laser, was carefully investigated, and it was shown that the photodetector performance is enhanced the most with the inclusion of spheroidal Ag NPs with ∼70 nm diameter. The Al/Si/SnO/Ag NPs/ZnO/ITO device exhibited an optimum responsivity, detectivity and sensitivity of 210.2 mA W-1, 5.47 × 109 Jones and 15.0 × 104, respectively, together with a rise and fall time of 2.3 and 51.3 μs, respectively, at a laser power density of 317 mW cm-2 and at a chopper frequency of 10 Hz. The present photodetectors are more than twice as responsive as the current best-performing ZnO-based pyro-phototronic photodetectors and they also exhibit other competitive features, such as detectivity, and fall and rise times. Therefore, by exploiting the plasmonic effect of the Ag NPs together with the pyroelectric effect in a ZnO film, and the photovoltaic effect at a Si/SnO junction, all in a single device, photodetectors were developed with state-of-the-art performance for the visible region.

Polymer-assisted crystal growth regulation and defect passivation for high-performance flexible solar-blind photodetectors based on copper-based halides

A PVP-assisted method regulates the crystal growth of Cs3Cu2I5 films for flexible solar-blind photodetectors.

Influence of annealing pretreatment in different atmospheres on crystallization quality and UV photosensitivity of gallium oxide films.

Due to their high wavelength selectivity and strong anti-interference capability, solar-blind UV photodetectors hold broad and important application prospects in fields like flame detection, missile warnings, and secure communication. Research on solar-blind UV detectors for amorphous Ga2O3 is still in its early stages. The presence of intrinsic defects related to oxygen vacancies significantly affects the photodetection performance of amorphous Ga2O3 materials. This paper focuses on growing high quality amorphous Ga2O3 films on silicon substrates through atomic layer deposition. The study investigates the impact of annealing atmospheres on Ga2O3 films and designs a blind UV detector for Ga2O3. Characterization techniques including atomic force microscopy (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) are used for Ga2O3 film analysis. Ga2O3 films exhibit a clear transition from amorphous to polycrystalline after annealing, accompanied by a decrease in oxygen vacancy concentration from 21.26% to 6.54%. As a result, the response time of the annealed detector reduces from 9.32 s to 0.47 s at an external bias of 10 V. This work demonstrates that an appropriate annealing process can yield high-quality Ga2O3 films, and holds potential for advancing high-performance solar blind photodetector (SBPD) development.

High-performance black arsenic photodetector assisted by multi-mechanisms effects detecting from visible to terahertz

High-performance black arsenic photodetector assisted by multi-mechanisms effects detecting from visible to terahertz

Regulating energy band alignment for high-performance broadband perovskite photodetectors

The excellent detection performance of photodetector is realized by adjusting the energy band arrangement at the interface between perovskite and electrode. The optical response mechanism beyond the band gap limit is explained.

Synergistic nucleation regulation using 4,4',4''-tris(carbazol-9-yl)-triphenylamine and moisture for stably air-processed high-performance perovskite photodetectors.

Perovskite photodetectors (PPDs) offer a promising solution with low cost and high responsivity, addressing the limitations of traditional inorganic photodetectors. However, there is still room for improvement in terms of the dark current and stability of air-processed PPDs. In this study, 4,4',4''-tris(carbazol-9-yl)-triphenylamine (TCTA) was utilized as a nucleation agent to enhance the quality of perovskite films. The synergistic effect of TCTA and moisture promotes rapid nucleation of PbI2-PbCl2, resulting in an increased nucleation rate and the elimination of pinholes in the film. By employing additive engineering, we obtained a PbI2-PbCl2 layer with high coverage, leading to a low density of traps in the corresponding perovskite film. Consequently, the modified PPD exhibits a remarkable reduction in dark current density by over one order of magnitude, reaching 2.4 × 10-10 A cm-2 at -10 mV, along with a large linear dynamic range (LDR) of 183 dB. Furthermore, the resulting PPD demonstrates remarkable stability, retaining 90% of the initial external quantum efficiency (EQE) value even after continuous operation for over 3200 hours. Owing to a fast response time in the nanosecond range, the PPD could convert modulated light signals into electrical signals at a speed of 588 Kbit s-1, highlighting the great potential in the field of optical communication.

A high-performance self-powered broadband photodetector based on vertical MAPbBr3/ZnO heterojunction

A high-performance self-powered broadband photodetector based on vertical MAPbBr3/ZnO heterojunction

The enhanced responsivity and response speed of SnO2 visible-blind transparent photodetectors via the SiO2 passivation layer.

Recently, transparent ultraviolet (UV) photodetectors have gained wide attention for their giant potential in integrated transparent electronics applications. SnO2 films as a common candidate for visible-blind transparent ultraviolet photodetectors have attracted increasing attention. In this work, high-performance visible-blind transparent UV photodetectors based on SnO2 thin film and a SiO2 passivation layer were successfully synthesized by the sol-gel spin coating method for the first time. The obtained SnO2/SiO2 hybrid device has a transmittance of nearly 80% in the visible band at 400-700 nm and demonstrates a high responsivity of 769 mA W-1 and a detection sensitivity of 1.24 × 1014 Jones under UV light illumination. The UV-C/UV-A rejection ratio is greater than 106, indicating that the device has good photo-selectivity. In addition, after the introdution of the SiO2 layer, the response speed is 2 times higher than that of pure SnO2. The presence of the SiO2 layer reduces the exposed area of SnO2, passivates the oxygen vacancies on the surface of SnO2 and inhibits the surface chemical adsorption. The above results provide a new perspective for improving the performance of SnO2 thin film for visible-blind transparent ultraviolet photodetectors.

High performance photodetector based on WSe2p-n homojunction induced by the electron doping from Bi2O2Se

Compared with heterostructure engineering, which not only requires a complex alignment process but also inevitably introduces defects in the material preparation processes, the homojunction design advantages a clean interface that is beneficial to the device performance. In this work, in order to realize a 2D material-based p-n junction with a clean interface, a transverse WSe2 homojunction is constructed using the n-type Bi2O2Se placed beneath part of the WSe2 as the electron donor. The contact with Bi2O2Se induces an n-type region in the primarily p-type WSe2, creating a p-n junction with the neighboring pristine region. Moreover, because the carrier concentration in Bi2O2Se is large enough to block the back-gate voltage for the doped region in WSe2, the device can be converted between p-n and “quasi-n-p” (the undoped region has a higher Fermi level than the doped region) junction by gate voltage regulation. The device shows an excellent photoelectric performance in the visible region, with a high commutation ratio (105), high responsiveness (1.2 × 104 A/W), and fast response speed (rise and decay times of 230 μs and 250 μs). Therefore, doping with other materials as donor or acceptor is a promising and efficient method, which has broad prospects in future electronic and optoelectronic applications.

High performance photodetectors based on In2S3, In2S1.5Se1.5 and In2Se3 nanostructures

One-dimensional (1D) nanostructures, including nanofibers, nanocubes, and nanoplates of In2S3, In2S1.5Se1.5, and In2Se3 semiconductors, were synthesized using a hydrothermal technique for studying their photodetector behaviour.

Vertical MSM-type CsPbBr<sub>3</sub> thin film photodetectors with fast response speed and low dark current

Halide perovskites exhibit excellent electrical and optical properties and are ideal candidates for active layers in optoelectronic devices, especially in the field of high-performance photodetection, where they demonstrate a competitive advantage in terms of development prospects. Among them, the all-inorganic perovskite CsPbBr<sub>3</sub> has received widespread attention due to its better environmental stability. It is demonstrated in this work that a vertical MSM-type CsPbBr<sub>3</sub> thin-film photodetector has characteristics of fast response time and ultra-low dark current. The use of a vertical structure can reduce the transit distance of photo carriers, enabling the device to achieve a fast response time of 63 μs, which is two orders of magnitude higher than the traditional planar MSM-type photodetectors with a response time of 10 ms. Then, by spinning a charge transport layer between the p-type CsPbBr<sub>3</sub> and Ag electrodes, effective separation of photocarriers at the interface is realized and physical passivation between the perovskite and metal electrodes is also achieved. Due to the superior surface quality of the spun TiO<sub>2</sub> film compared with the NiO<sub><i>x</i></sub> film, and through Sentaurus TCAD simulations and bandgap analyses, with TiO<sub>2</sub> serving as the electron transport layer, it effectively inhibits the transmission of excess holes in p-type CsPbBr<sub>3</sub>. Consequently, the electron transport layer TiO<sub>2</sub> is more effective in reducing dark current than the hole transport layer NiO<sub><i>x</i></sub>, with a dark current magnitude of only –4.81×10<sup>–12</sup> A at a –1 V bias. Furthermore, this vertical MSM-type CsPbBr<sub>3</sub> thin-film photodetector also has a large linear dynamic range (122 dB), high detectivity (1.16×10<sup>12</sup> Jones), and good photo-stability. Through Sentaurus TCAD simulation, it is found that the charge transport layer selectively blocks carrier transmission, thereby reducing dark current. The simulation results are in good agreement with experimental data, providing theoretical guidance for a more in-depth understanding of the intrinsic physical mechanisms.

Local modulation of Au/MoS2 Schottky barriers using a top ZnO nanowire gate for high-performance photodetection.

Schottky junctions are commonly used for fabricating heterojunction-based 2D transition metal dichalcogenide (TMD) photodetectors, characteristically offering a wide detection range, high sensitivity and fast response. However, these devices often suffer from reduced detectivity due to the high dark current, making it challenging to discover a simple and efficient universal way to improve the photoelectric performances. Here, we demonstrate a novel approach for integrating ZnO nanowire gates into a MoS2-Au Schottky junction to improve the photoelectric performances of photodetectors by locally controlling the Schottky barrier. This strategy remarkably reduces the dark current level of the device without affecting its photocurrent and the Schottky detectivity can be modified to a maximum detectivity of 1.4 × 1013 Jones with -20 V NG bias. This work provides potential possibilities for tuning the band structure of other materials and optimizing the performance of heterojunction photodetectors.

Highly efficient organic–graphene hybrid photodetectors via molecular peripheral editing

A molecular peripheral editing approach based on tetrathiafulvalene molecules is presented to elucidate the structure–property relationship of organic molecules, toward high-performance photodetectors based on organic–graphene hybrids.

Cherenkov Light Emission in Pure Cherenkov Emitters for Prompt Gamma Imaging.

Proton range verification (PRV) in proton therapy by means of prompt-gamma detection is a promising but challenging approach. High count rates, energies ranging between 1 MeV and 7 MeV, and a strong background complicate the detection of such particles. In this work, the Cherenkov light generated by prompt-gammas in the pure Cherenkov emitters TlBr, TlCl and PbF2 was studied. Cherenkov light in these crystals can provide a very fast timing signal with the potential to achieve very high count rates and to discern between prompt-gammas and background signals. Crystals of 1×1 cm2 and thicknesses of 1 cm, 2 cm, 3 cm and 4 cm were simulated. Different photodetector configurations were studied for 2.3 MeV, 4.4 MeV, and 6.1 MeV prompt-gammas. TlCl achieved the greatest number of detected Cherenkov photons for all energies, detector dimensions, and photodetector efficiency modeling. For the highest prompt-gamma energy simulated, TlCl yielded approximately 250 Cherenkov detected photons, using a hypothetical high-performance photodetector. Results show the crystal blocks of 1 cm × 1 cm × 1 cm have greater prompt-gamma detection efficiency per volume and a comparable average number of detected Cherenkov photons per event.

A two-dimensional PtSe2 thin film coupled with a graphene/Si Schottky junction for a high-performance photodetector.

Silicon materials are irreplaceable in the modern information society because of their rich resource, low price, and mature manufacturing technology for optoelectronics. However, improving the responsivity and response speed of silicon-based photodetectors is still a challenge. Here, a double-heterojunction photodetector (PD) by coupling two-dimensional PtSe2 thin film with a graphene/silicon Schottky junction is proposed. The introduction of PtSe2 enhances the built-in electric field of the device, thus suppressing the dark-state current and promoting the separation of photogenerated electron-hole pairs. Under 808 nm laser illumination, the PtSe2/graphene/Si PD exhibits an optimal responsivity, specific detectivity, and response speed of 0.81 A W-1, 1.24 × 109 Jones, and 43.6/51.2 μs, respectively. These performance indexes are obviously better than the corresponding graphene/Si device. Furthermore, the PtSe2/graphene/Si PD has good environmental durability and photoresponse ability from the ultraviolet to near-infrared. This work will provide new possibilities for designing novel silicon-based photodetection devices with high performance and fast response.

Electrically tunable interlayer recombination and tunneling behavior in WSe2/MoS2 heterostructure for broadband photodetector.

Electrically tunable band structure and light-matter interaction are of great importance in designing novel devices and constructing high-integrated and high-performance photodetector systems in the future. However, tunable mechanisms on the layered semiconductor, especially the heterojunction, are still unclear. Herein, the WSe2/MoS2 phototransistor with dual-gated configuration is fabricated, and its electrical and photoelectrical conversion has been studied to show large tunability. It was found that conduction and rectification characteristics can be tuned by dual gates showing four states, p-i, p-n, i-n, and n-n, as a result of the charging and depletion of WSe2 and MoS2. The rectifying ratio can be modulated across a large range from 102.5 to 10-3.2. Its photoelectronic characteristics were observed to exhibit bipolar and wavelength-dependent behaviors. The interlayer recombination of charge carriers dominates the photoresponse of the device under the illumination of visible light, while it is dominated by interlayer tunneling under the illumination of near-infrared wavelengths. This bipolar photoresponse is associated with different states of band alignment, which can be switched by dual-gating modulation. Finally, by tuning the gate voltage, responsivities reach 27 445 A W-1 and 2827 A W-1 at wavelengths of 400 and 1010 nm at room temperature, respectively, which directly extends the response region from visible light to near-infrared.

High-performance photodetector based on quasi-two-dimensional Ruddlesden–Popper perovskite PEA2FA2Pb3Br10 film

For next-generation Internet-of-Everything applications, such as artificial neural-network image sensors, artificial retina, visible light communication, flexible devices, and so on, the photodetectors with excellent properties are urgently demanded. In recent years, two-dimensional (2D) material-based photodetectors have been developed and certified for remarkable performances. Nonetheless, it cannot meet the need of wide linear dynamic range, ultralow dark current, and large on/off ratio, which are critical factors for commercial applications. Recently, quasi-2D Ruddlesden–Popper (RP) perovskites are explored and developed as well-known photovoltaic and optoelectronic materials. Herein, an excellent photodetector based on quasi-2D RP layered perovskite PEA2FA2Pb3Br10 film was fabricated. The photodetector displays an ultralow dark current of 4.08 × 10−11 A, high specific detectivity of 1.69 × 1010 Jones, high on/off ratio of 7.33 × 103, and fast rise/fall times of 32/38 ms, attributed to its multiple quantum wells in PEA2FA2Pb3Br10. Therefore, the photodetectors based on quasi-2D RP perovskite PEA2FA2Pb3Br10 have immense potentials in the field of optoelectronics.

High-performance CsSnBr<sub>3</sub>/Si PN heterojunction photodetectors prepared by pulsed laser deposition epitaxy

Halide perovskite semiconductors have outstanding physical properties such as high light absorption coefficient, large carrier diffusion length, and high photoluminescence quantum efficiency, and demonstrate significant potential applications in optoelectronic devices such as photodetectors and solar cells. However, the toxicity and environmental instability associated with lead-based perovskites significantly limit their applications. An attractive solution is substituting tin for lead in perovskites and growing high-quality tin-based perovskite films. In this study, we adopt the pulsed laser deposition method to achieve the epitaxial growth of CsSnBr<sub>3</sub> films on silicon substrates. The morphologies, optical and electrical properties of the CsSnBr<sub>3</sub> films, as well as the CsSnBr<sub>3</sub>/Si heterojunction detectors, are comprehensively investigated with various characterization techniques, including XRD 2<i>θ</i>-<i>ω</i> and <i>φ</i> scans, atomic force microscope, scanning electron microscope, photoluminescence and time-resolved photoluminescence spectroscopy, and Hall electrical measurements. The results indicate that such a CsSnBr<sub>3</sub> film grows epitaxially onto the silicon substrate via a face-to-face mode. Interestingly, an unusual temperature-dependent bandgap increase is found to be due to the high electron effective mass of CsSnBr<sub>3</sub>. The CsSnBr<sub>3</sub> film shows the P-type semiconductor behavior with a high mobility of 122 cm²/(V·s), enabling the formation of an ideal Type-II heterojunction with the silicon substrate. The CsSnBr<sub>3</sub>/Si semiconductor heterojunction detector exhibits distinctive heterojunction PN diode characteristics in the dark and a pronounced photoresponse under illumination. At zero bias, the detector displays a switch ratio exceeding 10<sup>4</sup>, responsivity of 0.125 mA/W, external quantum efficiency of 0.0238%, detectivity (<inline-formula><tex-math id="Z-20240301150440">\begin{document}$D^* $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231645_Z-20240301150440.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="5-20231645_Z-20240301150440.png"/></alternatives></inline-formula>) of 2.1×10<sup>9</sup> Jones, response time 3.23 ms, and recovery time of 4.87 ms. Under a small bias of –1 V, the switch ratio decreases to 50, but responsivity and external quantum efficiency increase by 568 times. The detectors can maintain self-powered operation state with a high switch ratio of 10<sup>4</sup>, millisecond-level response time and millisecond-level recovery time. In conclusion, this work presents a self-powering, high-performance photodetector based on CsSnBr<sub>3</sub> epitaxial films integrated with silicon substrates.