Performance Of Photodiodes Research Articles

Morphological optimization of CuO-Y2O3 BPMO composites for enhanced MIS diode performance

The development of techniques for synthesizing nanomaterials with convertible characteristics has resulted from the need to enhance photodiode performance. In this article, we presented the synthesis of CuO-Y2O3 nanocomposites for optoelectronic applications using feasible low-temperature co-precipitation technique. In A cubic phase structure for pure Y2O3 and a orthorhombic structure for CuO-Y2O3 composite have been proven to exist based on XRD patterns with predominant orientations along the directions (2 2 2) and (1 2 1), respectively. Dual phase polycrystalline structure with cubic and orthorhombic crystals is seen for samples of CuO with Y2O3 of various compositions. In the CuO composite with Y2O3, FESEM images reveal the existence of thorn-like, rectangular, irregular rectangular forms, and discrete shaped particles. The appearance of two predominant stretching vibrations of both CuO-Y2O3 and Y2O3 obtained from the FT-IR spectra at 555 cm−1 and 493 cm−1 respectively. The 75–25 composition of Cu-Y sample has the lowest band-gap energy (1.944 eV), according to UV-DRS spectra. Two significant peaks with binding energies 158.88 eV (for Y3d3/2) and 157.08 eV (for Y3d5/2) are evidenced in the Y3d XPS peak fit. According to the results of the I–V investigation, the p-Si/Al interface contains CuO-Y2O3 nanocomposites, which enhance the MIS diode’s performance. The developed photo-detectors are ideally suited for nano-electronic applications due to their superior optoelectronic characteristics.

Superior role of V2O5 and yttrium interface layers in enhancing MIS radical photodiode performance

In this study, Cu/n-Si Schottky diodes with V2O5–Y insulating interface layer were designed for the fabrication of metal/insulator/semiconductor (MIS) structures. The effects of different Y–V2O5 interface layers placed between metals and semiconductors on the critical electrical parameters of Schottky diodes were examined. Electrical parameters of the prepared sample such as barrier height (ΦB), ideality factor (n), photosensitivity (Ps), photosensitivity (R), quantum efficiency (QE) and detectivity (D∗) were obtained from the expression. Characteristics of I–V The modification in these parameters can be attributed to the use of Schottky diodes as intermediate layers. Additionally, n, ΦB values were calculated using the thermionic emission process and the photodiode parameters Ps, R, QE and D∗ the results were compared with each other. Experiments have shown that the Schottky structure with V2O5–Y interlayer leads to higher values of Ps = 799.70 % and under the light condition of 6 wt% of Y lower value n = 2.01. This provides evidence of the improved performance of MIS models.

Enhancing Infrared Photodiode Performance by Femtosecond Laser Hyperdoping

Enhancing Infrared Photodiode Performance by Femtosecond Laser Hyperdoping

Investigation of the performance and stability of self-powered polythiophene-based photodiodes under UV and visible light illumination

In this study, we fabricated polythiophene (PTh) and silver-decorated polythiophene (Ag@PTh) films on n-type silicon substrates using the electrochemical deposition method to investigate their electrical and photoelectrical properties in metal/interlayer/n-Si heterostructures under various conditions. The physical properties of the films were comprehensively investigated through UV-Vis, Raman, XPS and SEM analysis. The results from these analyses confirmed the successful deposition and formation of the films on the n-Si substrates. Additionally, a comparison of the current-voltage (I-V) characteristics of the PTh/n-Si and Ag@PTh/n-Si devices was conducted under both dark conditions and illumination with visible and UV light. While both devices exhibited typical rectifying diode behavior, the Ag@PTh/n-Si device demonstrated greater rectification with a RR of 2.49 x 105 at ± 2 V under dark conditions. In addition, the Ag@PTh/n-Si device, with self-powered property, displayed notably enhanced performance metrics, including a significantly higher ON/OFF ratio, responsivity, and detectivity, particularly evident under UV light illumination when compared to white light. Furthermore, to assess the long-term reliability of these devices, stability tests were conducted by repeating the I-V measurements after 90 days under identical conditions. The Ag@PTh/n-Si device exhibited considerably better stability over time than the PTh/n-Si device, maintaining consistent performance without notable degradation. So, in light of the findings, it can be concluded that the Ag@PTh/n-Si device has substantial potential for advancing optoelectronic technology.

Device Modeling of 4H-SiC PIN Photodiodes with Shallow Implanted Al Emitters for VUV Sensor Applications

A numerical model is presented for the simulation of ultraviolet ion-implanted 4H-SiC photodiodes with shallow p- emitter doping profiles. An existing model for SiC pin photodiodes, taken from literature, is modified with a dedicated SiO2-SiC interface layer to account for degradation of carrier mobility and lifetime at the interface. Furthermore, aluminum compensation in 4H-SiC is included and its impact on the spectral response and carrier recombination is analyzed. The simulated spectral response in the wavelength range from 200 to 400 nm is compared to experimental data. While the existing model, taken from literature, fails to predict the performance of VUV photodiodes with a shallow p- emitter, the newly designed model successfully achieves high accuracy, even with a basic modeling approach featuring an abrupt material parameter transition.

Transferrable CsPbBr3 Perovskite Single-Crystalline Films for Visible-Wavelength Photodetectors.

In this study, we propose large-scale CsPbBr3 (CPB) single-crystalline films (SCFs) grown by a one-step vapor-phase epitaxy (VPE) method for application in optoelectronic devices. After optimizing the transport speed of the precursor and cooling rate, we obtained continuous CPB films with a lateral size exceeding 2 cm2, and the thickness could be controlled from several micrometers to hundreds of nanometers. Crystallography and optoelectronic characterization proved the excellent crystallinity and very low trap density (2.14 × 1011) of the SCFs. Furthermore, we demonstrate a transfer-assembly strategy for fabricating perovskite SCF-based heterostructures for visible photodetectors. The high-quality SCF films in the active layer suppress the leakage current, leading to a low dark current of 5 × 10-10 A at -0.6 V. Therefore, the self-biased photodetector based on the vertical CsPbBr3 SCF-SnO2 heterostructure showed a high responsivity of 1.9 A/W, a detectivity of 4.65 × 1012 Jones, and a large on/off ratio of 4.63 × 103 under a 1 mW/cm2 450 nm light illumination. Our study not only demonstrates the excellent performance of single-crystalline perovskite-based photodiodes but also provides a universal assembly method for the integration of monocrystalline perovskite films in optoelectronic devices.

Spatial Nonuniformity of Photoresponse in SiC UV Avalanche Photodiodes Operating in Linear and Geiger Mode

Silicon Carbide's intrinsic material properties, along with the availability of low-defect density, 6" substrates, make it an attractive material system for visible-blind ultraviolet (UV) detectors. Avalanche photodiodes (APDs) made from SiC have been shown to operate both as linear mode detectors with high gain (>10⁷) and as single-photon avalanche detectors (SPADs) with competitive photon detection efficiency. However, reported spatial non-uniformities in photoresponse of these devices will reduce sensitivity [1,2].In this paper, we examine the impact of device geometry, epitaxial variations, and crystal anisotropy on the spatial uniformity of photoresponse in SiC APDs. Photoresponse maps are generated using a fast 285 nm pulsed LED source that is tightly focused to a ~10 µm spot. Response maps are measured for devices with different geometries fabricated on the same chip in both linear-mode and Geiger-mode. Measurements on standard pin diodes will be presented, along with separate absorption, charge, and multiplication (SACM) structures.Experimental results indicate that all devices exhibit localized regions of high photoresponse at gain > 1000 and that the spreading of the photoresponse is highly directional. Finger diodes with 120 μm x 30 μm mesas exhibit good response uniformity with a variation < 30% across the device. In contrast, diodes with 60 and 90 μm square-shaped mesas exhibit similar uniform response spreading along one edge that is bounded by the size of the mesa, but a >10x drop in relative response over ~30-40 μm in the orthogonal direction which is much shorter than the extent of the mesa. Devices with 100 μm circular mesas exhibit somewhat similar results to the square diodes, but with the presence of multiple hot spots in response.Experimental results are analyzed through 3D numerical modeling of devices which accounts for the effects of doping and thickness variations across the substrate as well as the anisotropy of impact ionization. Modeling indicates that small variations in the thickness in the drift regions of a diode can yield meaningful variations in avalanche gain across the mesa. The impact of anisotropic impact ionization will be considered using full-band 3D Monte Carlo calculations. X. Bai, H.-D. Liu, D. C. McIntosh and J. C. Campbell, "High-Detectivity and High-Single-Photon-Detection-Efficiency 4H-SiC Avalanche Photodiodes," IEEE J. Quantum Electron. 45 300-303 (2009). DOI: 10.1109/JQE.2009.2013093.L. Su et al, "Recent progress of SiC UV single photon counting avalanche photodiodes," J. Semicond. 40 121802 (2019). DOI: 10.1088/1674-4926/40/12/121802. Figure 1

On the piezo-phototronic effect in heterojunction photodiode with type-II energy band: Simulation on complex incident light illumination

A photodiode, a semiconductor device, is designed to convert light into an electric current. The piezo-phototronic effect, arising from the interplay of semiconductor properties, piezoelectric polarizations, and photo-excitations, presents a promising avenue for enhancing photodiode performance. This research is dedicated to analyzing the impact of the piezo-phototronic effects on p-Si/n-ZnO heterojunction photodiodes when subjected to 365 nm illumination, a situation more intricate than the commonly studied 648 nm illumination. Employing numerical simulation methods, we systematically investigated the influence of varying ZnO and Si lengths on the piezo-phototronic effect, with a focus on the depletion region and neutral region current perspectives. Our findings reveal that adjusting these lengths can heighten sensitivity at low currents or lead to increased base currents. Additionally, the study delves into the effects of doping concentration, minority carrier lifetime, and mobility on device characteristics. This investigation contributes essential insights for a comprehensive understanding of piezo-phototronic effects and establishes a foundational framework for the design of industrial devices.

Enhancing large-area Geiger-mode avalanche photodiode performance through dynamic memristor quenching: a study on improving count rate, reducing jitter and mitigating afterpulsing

While the larger photosensitive area of Geiger-mode avalanche photodiodes (GmAPDs) enhances their detection range and signal collection, improving their utility in weak light detection, their practicality is limited by a long recovery time, high afterpulsing probability (AP) and excessive jitter. Utilizing a dynamic memristor as a quenching resistor, this research improves the count rate of a large-size GmAPD by 100× at an overvoltage of 2.5 V, compared with a fixed resistor-quenched GmAPD. Furthermore, at a photon pulse frequency of 1 MHz jitter time is reduced from 3.60 ns to 0.48 ns, and the afterpulsing probability is effectively mitigated from 30.88% to 8.58%.

Fabrication and high photoresponse performance of a La-doped HfO2 thin film-based UV photodiode

The ability to detect ultraviolet light is crucial for various applications such as energy harvesting, environmental monitoring, sensing, and ultraviolet astronomy. In this paper, we determined the photoelectric properties of a photodiode based on an interfacial layer of a La-doped HfO2 (HfLaO) thin film. We carried out several tests to analyze the electrical behavior and photoresponse of the Au/HLO/p-Si photodiode under ultraviolet (UV) and white light illumination and in the dark. The chemical composition, surface morphology, cross-sectional thickness, optical properties, and crystalline structure of the HfLaO (HLO) film prepared by the sol-gel method were characterized. We found that the prepared photodiode exhibited excellent repeatability and stability. Moreover, the photocurrent increased with increasing UV light intensity. When the UV light intensity was 23.5 mW/cm2, the photocurrent reached 700 μA and remained unsaturated at a 7 V bias voltage. Moreover, we systematically analyzed the changes in the energy bands and carriers under dark and ultraviolet light conditions to further understand the working mechanism of the photodiode. Overall, the Au/HLO/p-Si photodiode had excellent ultraviolet detector performance and could be a strong candidate for optoelectronic applications.

Unique Hyperspectral Response Design Enabled by Periodic Surface Textures in Photodiodes.

The applications of hyperspectral imaging across disciplines such as healthcare, automobiles, forensics, and astronomy are constrained by the requirement for intricate filters and dispersion lenses. By utilization of devices with engineered spectral responses and advanced signal processing techniques, the spectral imaging process can be made more approachable across various fields. We propose a spectral response design method employing photon-trapping surface textures (PTSTs), which eliminates the necessity for external diffraction optics and facilitates system miniaturization. We have developed an analytical model to calculate electromagnetic wave coupling using the effective refractive index of silicon in the presence of PTST. We have extensively validated the model against simulations and experimental data, ensuring the accuracy of our predictions. We observe a strong linear relationship between the peak coupling wavelength and the PTST period along with a moderate proportional relation to the PTST diameters. Additionally, we identify a significant correlation between inter-PTST spacing and wave propagation modes. The experimental validation of the model is conducted using PTST-equipped photodiodes fabricated through complementary metal-oxide-semiconductor-compatible processes. Further, we demonstrate the electrical and optical performance of these PTST-equipped photodiodes to show high speed (response time: 27 ps), high gain (multiplication gain, M: 90), and a low operating voltage (breakdown voltage: ∼ 8.0 V). Last, we utilize the distinctive response of the fabricated PTST-equipped photodiode to simulate hyperspectral imaging, providing a proof of principle. These findings are crucial for the progression of on-chip integration of high-performance spectrometers, guaranteeing real-time data manipulation, and cost-effective production of hyperspectral imaging systems.

Standardizing the optimal photo-diode performance of CuO nanostructures through various morphological patterns

The CuO nanocrystals were prepared using a simple surfactant-assisted co-precipitation technique then addition of anionic surfactants such as Hexamine (HEX), Polyvinyl Pyrrolidone (PVP), Polyvinyl Alcohol (PVA) and Cetyl Trimethyl Ammonium Bromide (CTAB) leads to the formation of CuO nanostructures on the surface of spherical particles. Samples were characterized via X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FESEM), UV–visible diffuse reflectance spectroscopy and I-V characteristics. According to various spectroscopic results, all surfactant decorated CuO nanocrystal have a monoclinic crystal structure. Then the average grain size of CuO samples supported by HEX, PVA, PVP and CTAB is approximately 72 nm. The properties of surfactants have been shown to affect size and shape. In addition, the FT-IR spectra of all samples show three similar vibration modes of CuO, this indicates the presence of a monoclinic CuO crystal structure. According to absorbance data, the quantum confinement effect caused by the use of surfactant significantly affects the optical bandgap value, ranging from 3.00 to 2.59 eV. Current-voltage characteristics [I-V] unveil the photodiode parameters of prepared diode are evaluated in the dark and light condition. In this case, the barrier height (ΦB) is 0.80 eV and the ideal value for the diode (n) is 2.05, which is more suitable for photodiode applications.

Impact of ambient temperature on the filter polychromators performance and accuracy of thomson scattering diagnostics

Thomson scattering is one of the most important diagnostic methods for measuring plasma electron temperature (Te) and electron density (ne). In the diagnostic system, the polychromator is often used to analyze the spectral broadening and intensity of the detected scattered light. The performance of the avalanche photodiode (APD) used in the polychromator is greatly affected by the ambient temperature. The change of ambient temperature will seriously affect the accuracy of Thomson scattering diagnosis. Through experimental analysis, when the ambient temperature increases, the gain of APD will be significantly reduced, resulting in a significant deviation in electron density measurement. Taking the system response at an ambient temperature of 24.1 °C as reference, the deviation of electron density measurement varies from 43% to −16%, with the ambient temperature from 16.6 °C to 29.9 °C. However, the change of ambient temperature has little impact on the measurement of electron temperature. Detailed test of the polychromator shows that the estimated deviation of the electron temperature is within 3%. Due to the change of ambient temperature, the response of the detectors in each channel of the polychromator is inconsistent, which will cause random errors. The influence on electronic temperature calculation is analyzed by numerical simulation.

Enhanced performance of PFO-ZnO nanorods nanocomposite photodiodes grown on ZnO NRs/ZnO/ITO-coated glass

An improved photodiode was fabricated using a nanocomposite of poly (9,9-di-n-octylfluorenyl-2,7-diyl) (PFO) and zinc oxide nanorods (ZnO NRs). The nanocomposite was prepared by scratching hydrothermally grown ZnO NRs on a glass substrate into the prepared PFO solution. The nanocomposite layer was deposited using the spin-coating method and silver (Ag) paste was applied as the electrode. The resulting photodiode configuration is Ag/PEDOT:PSS/PFO-ZnO NR/ZnO NRs/ZnO/ITO. Ultraviolet–visible (UV–Vis) spectroscopy showed a slight blue shift and a slight increase in the optical bandgap. The nanocomposite-based photodiode showed improved performance, due to increased active surface area for the separation of photogenerated electron-hole pairs between PFO and ZnO and also because of the higher current density of ZnO. Finite-Difference Time-Domain (FDTD) simulations showed ZnO NRs increased electric field strength and exciton generation rate throughout the PFO polymer in the nanocomposite. The photodiode with the nanocomposite showed the best performance at −5 V bias voltage under 385 nm illumination, obtaining responsivity of 1.45 A W−1, Detectivity of 2.19 x 1010 Jones, and External quantum efficiency (EQE %) of 468 %.

Towards high-performance photodiodes based on p-Si/perovskite heterojunction

Photodiodes based on Si/perovskite heterojunction have been intensively studied due to their broad spectral photodetection. However, device optimization of the perovskite layer thickness and the top electrode is rarely tackled. In this work, we first investigated the effect of perovskite thickness on the performance of photodiodes with the structure of “Si/perovskite/Ag (comb-shaped)”. The photodiode with 170 nm perovskite layer shows the highest responsivity (R) for lights with wavelengths between 532 nm and 650 nm, while the photodiodes with 539 nm perovskite layer has the highest R in the 808–850 nm range. The specific detectivity (D*) exhibits maximal values for all wavelengths at perovskite layer thickness of 170 nm. Furthermore, by introducing copper phthalocyanine (CuPc) as the buffer layer, we successfully utilized Al as the top electrode in photodiodes based on Si/perovskite heterojunction with improved device performance. The CuPc-thickness dependent performance was investigated, and an optimal thickness of ∼ 10 nm was determined, achieving a high photo responsivity of 1.77 A/W and D* of 6.8 × 1011 Jones, which are around 3 and 7 times higher than those of the Ag-based device, respectively.

Black Phosphorus Molybdenum Disulfide Midwave Infrared Photodiodes with Broadband Absorption-Increasing Metasurfaces.

Black phosphorus (BP) has been established as a promising material for room temperature midwave infrared (MWIR) photodetectors. However, many of its attractive optoelectronic properties are often observable only at smaller film thicknesses, which inhibits photodetector absorption and performance. In this work, we show that metasurface gratings increase the absorption of BP-MoS2 heterojunction photodiodes over a broad range of wavelengths in the MWIR. We designed, fabricated, and characterized metasurface gratings that increase absorption at selected wavelengths or broad spectral ranges. We evaluated the broadband metasurfaces by measuring the room temperature responsivity and specific detectivity of BP-MoS2 photodiodes at multiple MWIR wavelengths. Our results show that broadband metasurface gratings are a scalable approach for boosting the performance of BP photodiodes over large spectral ranges.

Enhancement of the performance of a ZnO-based nanostructured flexible UV photodiode grown on the carbon clothe by piezo-phototronic effect

The current study aims to evaluate the piezo-phototronic effect on the performance of the prepared ZnO-based UV Photodiodes (PDs). To this end, the electrochemical method was employed to facilitate the growth of ZnO Nanowires (NWs) on the Carbon Clothe (CC) substrate. The results obtained from Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses demonstrated well-grown ZnO NWs arrays with high coverage density and crystal quality on the substrate. The current-voltage (I–V) measurement was employed in the UV illumination and dark conditions to determine the photo-responsivity and detectivity of the prepared device to the UV light. In addition, the photocurrent and overall device performances were modified under UV illumination and applying compressive strain, given its role in increasing the barrier height. As a result, more photo-generated charge carriers can migrate to the electrode without recombination in comparison with free strain conditions. This phenomenon is known as the piezo-phototronic effect. Further, the findings of this study revealed that CC could be an appropriate alternative to the fabricated flexible PDs instead of other expensive flexible substrates such as Indium Tin Oxide/Poly-Ethylene Terephthalate (ITO/PET).

Self‐Healing of Proton‐Irradiated Organic Photodiodes and Photovoltaics

AbstractIn this study, a comprehensive quantitative analysis of the photodiode (PD) is conducted and photovoltaic (PV) characteristics of organic non‐fullerene PCE10:ITIC‐4F devices before and after exposure to a 150 ns pulse of 170 keV proton irradiation with the fluence of 2·1012 p cm−2 that is equivalent to ≈6 years of operation at a low Earth orbit. While an expected initial performance reduction happened in the photodiode and photovoltaic operation modes, a hitherto unknown self‐healing effect in the organic devices is observed several days after the proton irradiation. The organic bulk‐heterojunction (BHJ) material properties and the multi‐mechanisms recombination processes before and after irradiation and during self‐healing are investigated. This analysis provides a quantitative understanding of the changes occurring in the device physics and points toward the relevant aspects of the self‐healing mechanism related to the dynamics of proton‐induced traps in the bulk of the organic active layer. Ultimately, the synergy of record lightweight features and newly discovered self‐healing of proton‐induced damage in organic PDs and solar cells highlights their great potential for applications in rapidly emerging space technology.

Doping-Free High-Performance Photovoltaic Effect in a WSe2 Lateral p-n Homojunction Formed by Contact Engineering.

Two-dimensional transition metal dichalcogenides (TMDs) are promising materials for semiconductor nanodevices owing to their flexibility, transparency, and appropriate band gaps. A variety of optoelectronic and electronic devices based on TMDs p-n diodes have been extensively investigated due to their unique advantages. However, improving their performance is challenging for commercial applications. In this study, we propose a facile and doping-free approach based on the contact engineering of a few-layer tungsten di-selenide to form a lateral p-n homojunction photovoltaic. By combining surface and edge contacts for p-n diode fabrication, the photovoltaic effect is achieved with a high fill factor of ≈0.64, a power conversion efficiency of up to ≈4.5%, and the highest external quantum efficiency with a value of ≈67.6%. The photoresponsivity reaches 283 mA/W, indicating excellent photodiode performance. These results demonstrate that our technique has great potential for application in next-generation optoelectronic devices.

Modified photodiode equivalent circuit model considering coplanar waveguide electrodes

Accurate equivalent circuit models can assist in better analyzing the performance of photodetectors. This study proposes a modified photodiode (PD) equivalent circuit model that considers coplanar waveguide (CPW) electrodes. First, the CPW electrodes of the PD are analyzed using high-frequency structure simulation software and advanced design simulation software. Skin effect occurs inside the electrode at high frequencies, increasing the PD loss and reducing the bandwidth. Subsequently, the extraction formula for the proposed model is derived, and the proposed model is compared with two conventional CPW electrode models. The proposed model effectively eliminates the frequency-dependency issue in the parameter extraction process of previous models, thereby demonstrating its accuracy. Furthermore, simulation and experimental results validate the reliability of the proposed model. Among the entire frequency band, the proposed model has good stability and a low error rate and can achieve excellent fitting with the measured results. Compared with previous studies, the average error rate is reduced by over 10%, demonstrating a significant improvement. Finally, the influence of the skin effect and high-impedance transmission lines on PD performance is analyzed and a viable approach to improve the bandwidth of PDs is proposed. The proposed model provides a viable approach to model and optimize CPW structures and is significant for the design of high-performance PDs.