Dynamic temperature drift severely compromises the accuracy of piezoresistive pressure sensors in marine environments. This study introduces a novel Adaptive Weighted Slime Mould Algorithm-Extended Kalman Filter (AWSMA-EKF) method to address time-varying thermal instability. The research begins with the design, fabrication, and comprehensive characterization of a silicon piezoresistive pressure sensor, where the analysis of its temperature sensitivity mechanisms provides a foundation for dynamic modeling. Test results showed that the fifth-order polynomial of the sensor has a very small fitting residual in static calibration, but exhibited a significant lag when exposed to dynamic temperature variations, highlighting the fundamental limitation of static compensation approaches. To overcome this, a dynamic compensation framework is proposed, which constructs an EKF model with temperature and pressure as combined state variables and employs the AWSMA to dynamically optimize the EKF's noise covariance matrices online. Through simulated tests in dynamic marine environments, the AWSMA-EKF reduced the sensor's mean absolute error (MAE) from 4.42% FS (before compensation) to a remarkably low 0.05% FS. The root mean square error (RMSE) decreased by a maximum of 76% and 68% compared to PSO-EKF and SMA-EKF, respectively, demonstrating the superior optimization performance of the proposed AWSMA. The algorithm's effectiveness was further validated in a real ocean environment, with experiments demonstrating a 94% reduction in pressure measurement fluctuations at a depth of 400 m, thus verifying its engineering practicality. This study provides an innovative and effective solution for high-precision dynamic compensation of MEMS pressure sensors in highly dynamic and harsh environments.

This study proposes a novel micro-electromechanical system (MEMS) piezoelectric hydrophone with a dual-piezoelectric-layer structure to overcome the sensitivity limitations of traditional single-piezoelectric-layer devices in low-frequency bands and high-noise environments. The design is based on a silicon-on-insulator (SOI) wafer. It employs a five-layer stacked configuration consisting of a top electrode/first scandium-doped aluminum nitride (ScAlN) piezoelectric layer/middle electrode/second ScAlN piezoelectric layer/bottom electrode. By optimizing the neutral-axis position toward the middle electrode, the upper and lower piezoelectric layers experience opposite and nearly symmetric stress states, enabling a constructive combination of their differential electrical outputs. Additionally, a differential electrical connection is employed to enable an output voltage approaching twice that of the single-layer structure under ideal symmetric conditions, thereby significantly enhancing the electromechanical coupling efficiency and device sensitivity. Theoretical analysis confirms that this structure reduces energy loss in non-piezoelectric layers and enhances charge collection efficiency. Performance test results show that within the 100 Hz to 20 kHz frequency range, the average sensitivity reaches -172.5 +/- 1.7 dB (re: 1 V/mu Pa), with an equivalent noise density (END) of 49.6 dB (re: 1 mu Pa/root Hz) at 1 kHz, a piezoelectric coupling coefficient of 9.1%, and excellent linearity (R-2 = 0.998). Compared with reported single-piezoelectric-layer MEMS hydrophones and representative commercial bulk piezoelectric devices, this device exhibits improved sensitivity and noise performance under the compared conditions, indicating its potential for applications such as marine exploration, underwater communication, and pipeline leakage monitoring.

Microsphere-assisted super-resolution imaging technology, due to its ability to break through the diffraction limit, has become a powerful tool for achieving optical observations at the micro-nano scale. However, there remains a significant discrepancy between the simulation results of microsphere focusing behavior and experimental observations in existing studies, necessitating a more precise physical explanation. This study proposes that the interface reflection characteristics are a key factor influencing the focusing behavior of microspheres. We constructed a numerical simulation model based on ray optics theory using MATLAB, explicitly considering the reflection and transmission of light at the microsphere-medium boundary, and systematically analyzed the imaging process and focal position of the microsphere. Experimental results demonstrate that after accounting for energy loss due to reflection, the focal position obtained from the simulation calculations shows a high degree of consistency with the experimental results. The average deviation of our model from experimental results is reduced by 76% compared to conventional paraxial theory and by 86% compared to Finite-Difference Time-Domain (FDTD) simulations. Additionally, the findings validate the reliability of determining microsphere focusing theory using irradiance.

PurposeEnhancing the high-frequency performance of piezoelectric micro-electro-mechanical ultrasonic transducers (PMUTs), particularly the transmission performance of PMUT arrays, is a key focus in the advancement of MEMS technology. In this paper, a design strategy for a high-frequency ultrasonic transducer array based on aluminum nitride (AlN) is proposed.Design/methodology/approachThis paper proposes a design scheme for a high-frequency ultrasonic transducer array based on AlN material. This study established a three-dimensional finite element model of a PMUT and further designed two representative diaphragm structures - circular and hexagonal - as its sensing elements. Using multiphysics finite element simulation, this study focuses on optimizing the diaphragm shape of the PMUT-sensitive element. Concurrently, it proposes a honeycomb-like ultra-narrow equidistant arrangement scheme based on sealed silicon cavity technology and conducts acoustic performance simulations of the PMUT array.FindingsBy comparing the performance of different diaphragm shapes and array structures in terms of transmit voltage response, reception sensitivity, axial pressure distribution and array acoustic beam patterns, it is concluded that circular diaphragms and PMUT arrays based on equidistant narrow arrays exhibit outstanding acoustic performance.Originality/valueThis work not only provides valuable guidance for the design, simulation and fabrication of PMUT-sensitive units but also offers novel insights into the application of PMUT arrays in high-frequency scenarios.

Broadband photodetectors are critical for multispectral imaging, environmental monitoring, and optical communication. Zinc oxide (ZnO), known for its high electron mobility and excellent stability, is frequently integrated into heterojunctions to achieve broadband photodetection. Nevertheless, such ZnO-based heterostructures commonly encounter performance constraints, including interfacial defect states, lattice mismatch, and impeded carrier transport, which collectively degrade the response speed and spectral efficiency. This work demonstrates a self-powered photodetector based on a monolithic ZnO/Ag2Se/Si dual-heterojunction fabricated via magnetron sputtering. The complementary band structures and synergistic built-in electric fields at the dual heterointerfaces facilitate efficient carrier separation and collection, enabling a broad detection spectrum from 220 nm to 1550 nm without external power. The device exhibits a responsivity of 1.71 mA/W at 750 nm with a response time of 16.69/17.34 ms (rise/fall). Given its high sensitivity in the near-infrared region, the photodetector successfully decodes 950 nm optical signals into ASCII text, confirming its potential for optical communication. This work provides a feasible strategy for high-performance, self-powered broadband photodetection through rational heterojunction design.

An innovative design for a dual-piezoelectric-layer MEMS hydrophone based on a composite film of scandium-doped aluminum nitride (Sc0.2Al0.8N) is presented. By designing the dual piezoelectric layer, the frequency response range has been expanded and the sensitivity of the device has been significantly enhanced. Meanwhile, doping with scandium can significantly increase the piezoelectric coefficient, enhancing the sensitivity. According to the standard underwater acoustic calibration test, the device exhibits an average sound pressure sensitivity of −162 dB (re: 1 V/μPa) across the 20 Hz–50 KHz frequency band and equivalent noise density of 47 dB (re: 1 μPa/√Hz) with a linearity of 99%. The experimental results show that the comprehensive performance of the dual-piezoelectric-layer hydrophone provides a new solution for underwater sensing and detection, and opens up a new path for the performance optimization of passive sonar systems.

Precise in situ measurement of marine environmental parameters is fundamental to oceanographic research and resource development. While micro-electro-mechanical systems (MEMSs) technology offers a novel pathway for sensor miniaturization, existing electrode designs remain limited. Traditional two-electrode structures suffer from severe signal drift due to electrode polarization effects, while improved four-electrode configurations struggle to completely eliminate polarization interference at the micro-scale, thereby hindering further enhancements in measurement accuracy. To address these challenges, this study presents a monolithically integrated MEMS conductivity-temperature (CT) sensor designed for ocean observation. The core innovation involves a novel seven-electrode differential structure that utilizes square-wave excitation to effectively suppress polarization effects and common-mode noise. Additionally, the monolithic integration of a thin-film platinum resistance temperature detector (RTD) and the conductivity sensor is achieved via MEMS processes, effectively eliminating spatiotemporal synchronization errors. Furthermore, a back propagation (BP) neural network algorithm is introduced to address the temperature dependence of conductivity measurements, significantly resolving the issue of temperature-salinity cross-sensitivity. The sensing structure was optimized via COMSOL simulations to mitigate complex multielectrode electric field coupling. Experimental results demonstrate measurement accuracies better than +/- 0.004 C-degrees for temperature and +/- 0.01 mS/cm for conductivity. Following BP neural network compensation, the conductivity measurement error across a wide temperature range is significantly reduced to +/- 0.02 mS/cm. In field trials conducted in actual sea areas, the sensor successfully captured thermocline and halocline profiles. The obtained data showed high consistency with commercial high-precision equipment, verifying the reliability and superiority of the proposed scheme.

As an excellent pseudocapacitive material, NiCo2O4 suffers from low electrical conductivity and poor cycle stability caused by easy structural collapse during cycling. To address these issues, this study forms a heterostructure by intercalating NiCo2O4 into the interlayers of MXene through an electrostatic self-assembly method, integrating pseudocapacitance with electrical double-layer capacitance. This not only enhances the overall electrical conductivity and cycle stability of the material but also determines the optimal ratio of the two components by comparing their electrochemical performances. Experimental results show that in the three-electrode system, the electrode with the optimal ratio achieves a specific capacitance of 874.8 F g-1 at a current density of 1 A g-1. The asymmetric supercapacitor composed of NiCo2O4/MXene as the positive electrode and activated carbon as the negative electrode exhibits a high energy density of 41.3 Wh kg-1 at a power density of 800 W kg-1, and the capacitance retention rate still reaches 83.7 % after 10,000 charge-discharge cycles.

This work focuses on the structural design of a scandium aluminum nitride (ScAlN)-based piezoelectric hydrophone for microelectromechanical systems (MEMSs), with particular emphasis on analyzing the impact of the fill factor on the device's acoustic and electromechanical performance. Two hydrophone arrays with distinct configurations were designed and fabricated: a matrix arrangement and a cross-arrangement. Both arrays use identical cell structure dimensions and functional layer thicknesses and are fabricated on the same 4-in silicon-on-insulator (SOI) wafer to ensure process consistency. Among these, the cross arranged (CA) chip achieves a 45.45% higher fill factor than the matrix-arranged (MA) chip through a more compact arrangement design. Performance test results indicate that the CA chip demonstrates significantly enhanced performance. During air testing, its electromechanical coupling coefficient reached 13.70%, representing a 106.9% improvement over the 6.62% achieved by the MA chip. During underwater testing, the sensitivity of the CA chip in the 100-200-kHz frequency band was -175.7 +/- 4.3 dB (re: 1 V/& micro;Pa). In contrast, the MA chip's sensitivity was -179.7 +/- 2.5 dB (re: 1 V/& micro;Pa), resulting in an average improvement of approximately 2.7%. This study clearly demonstrates that a higher fill factor can effectively enhance the key acoustic performance of hydrophones. This finding provides essential guidance for the optimized design of future high-performance MEMS hydrophones.

This study designed and fabricated a microelectro- mechanical system (MEMS) Pt thin-film temperature sensor suitable for the medium-to-high temperature range of 33 degrees C-600 degrees C. A Pt film with a thickness of approximately 1 mu m was deposited on an Al2O3 ceramic substrate via magnetron sputtering, and annealing experiments were conducted within the temperature range of 500 degrees C-1000 degrees C. The microstructure, morphology, and crystal orientation of the thin film were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), while the resistance-temperature curve, resistance change rate, and temperature coefficient of resistance (TCR) of the sensor were tested. The results show that annealing at 800 degrees C for 4 h is the optimal process: under this condition, the platinum thin film exhibits a strong (111) crystal orientation preference with uniform and dense grains. The TCR increases from 2740 ppm/degrees C before annealing to 3742 ppm/degrees C, and the resistance change rate reaches -26.14%. Within the range of 33 degrees C-600 degrees C, the maximum temperature measurement error is less than 0.2%, the temperature drift is less than 0.08% FS, and the resistance-temperature curve shows excellent linearity. This sensor, featuring both high precision and stability, is suitable for high-precision temperature measurement scenarios in medium-to-high temperature environments, such as hot-end monitoring of aerospace engines and diagnosis of automotive exhaust systems.

The rapid development of flexible sensor technology has made flexible sensor arrays a key research area in various applications due to their exceptional flexibility, wearability, and large-area-sensing capabilities. These arrays can precisely monitor physical parameters like pressure and strain in complex environments, making them highly beneficial for sectors such as smart wearables, robotic tactile sensing, health monitoring, and flexible electronics. This paper reviews the fabrication processes, operational principles, and common materials used in flexible sensors, explores the application of different materials, and outlines two conventional preparation methods. It also presents real-world examples of large-area pressure and strain sensor arrays. Fabrication techniques include 3D printing, screen printing, laser etching, magnetron sputtering, and molding, each influencing sensor performance in different ways. Flexible sensors typically operate based on resistive and capacitive mechanisms, with their structural designs (e.g., sandwich and fork-finger) affecting integration, recovery, and processing complexity. The careful selection of materials—especially substrates, electrodes, and sensing materials—is crucial for sensor efficacy. Despite significant progress in design and application, challenges remain, particularly in mass production, wireless integration, real-time data processing, and long-term stability. To improve mass production feasibility, optimizing fabrication processes, reducing material costs, and incorporating automated production lines are essential for scalability and defect reduction. For wireless integration, enhancing energy efficiency through low-power communication protocols and addressing signal interference and stability are critical for seamless operation. Real-time data processing requires innovative solutions such as edge computing and machine learning algorithms, ensuring low-latency, high-accuracy data interpretation while preserving the flexibility of sensor arrays. Finally, ensuring long-term stability and environmental adaptability demands new materials and protective coatings to withstand harsh conditions. Ongoing research and development are crucial to overcoming these challenges, ensuring that flexible sensor arrays meet the needs of diverse applications while remaining cost-effective and reliable.

Photothermoelectric (PTE) detectors hold immense potential for converting incident light signals into electrical signals, finding applications in sensing, astronomy, night vision, and communication. However, their widespread adoption is hindered by issues such as slow response times, low responsivity, and poor stability. In this study, a high-performance self-powered PTE detector based on the Ag2Se nanorods (NRs) and multi-walled carbon nanotubes (MWCNTs) is reported for the first time. The findings reveal that the electrical conductivity of the film increases with the addition of MWCNTs, albeit at the expense of the Seebeck coefficient. Notably, the film containing 0.5 wt% MWCNTs exhibited a superior power factor (303.22 mu Wm-1K-2) at 300 K. Owing to the high PTE performance, the photosensitive properties are characterized in an ultra-broadband range from the violet (405 nm) to infrared (2,500 nm) wavelengths, featuring rapid response time (1.4 s) and substantial output voltage (6.83 mV). Furthermore, the device demonstrated remarkable stability, with only a 3.4% decrease in output voltage after three months of air exposure and negligible changes in thirty cycles. Thus, the proposed device presents a novel strategy for developing PTE detectors characterized by broadband coverage, fast response times, and exceptional stability.

Self-powered broadband photodetectors are increasingly studied for their minimal power requirements and significant photocurrent amplification. However, there are still serious challenges to achieving high performance in such devices, including the development of environmentally friendly, non-toxic materials and the achievement of high stability. In this study, AgxSe/Si heterojunction photodetectors with different Ag and Se ratios have been constructed for the first time using a simple and high-quality magnetron co-sputtering process. It is shown that Ag1.98Se/Si devices have the highest performance. The high performance is attributed to the high-quality film formation, which creates good interfacial contact while reducing noise interference from Ag aggregation and Se vacancies defects. The device shows a wide responsive range (450-2500 nm) and signal-to-noise ratio as high as 183. The device has a responsivity of 1.21 V/W and a detectivity of 3.45 x 1011 Jones, which is significantly better than the prepared Ag2.35Se/Si, Ag2.22Se/Si and Ag1.68Se/Si devices. Furthermore, the device exhibits outstanding stability, retaining 98.44 % of its initial photovoltage after 50 laser switching cycles. This research aims to deliver novel synthesis strategies that may guide future development and processing approaches for emerging materials in high-performance self-driven broadband photodetectors.

This study presents the design and fabrication of an ultrahigh-precision platinum thin-film temperature sensor without an adhesion layer, which effectively eliminates the performance degradation caused by adhesion layer diffusion during high-temperature annealing. A 1- mu m-thick platinum film was deposited on an alumina substrate via segmented magnetron sputtering, followed by annealing in air at temperatures ranging from 500 degrees C to 900 degrees C. The resistance-temperature relationships of the sensor were characterized over the 0 degrees C- 35 degrees C range under various annealing conditions, with a particular focus on the temperature coefficient of resistance (TCR). The morphological and grain size analyses of the platinum film were conducted using X-ray diffraction (XRD) and scanning electron microscopy. Results indicate that optim al sensor performance was achieved with an annealing temperature of 800 degrees C for 2 h, which leads to an increase in the TCR from 2.36 x 10(-3) /degrees C to 3.65 x 10(-3) /degrees C. Precision calibration and stability tests show that the sensor achieved an excellent measurement accuracy of 0.0019 degrees C and a maximum temperature drift of only 0.0009 degrees C per month over a six-month period. These results indicate that the platinum thin-film sensor exhibits outstanding performance, making it particularly suitable for high-precision ocean temperature measurement applications.

Residual stress has long been a critical issue in the development of MEMS, as its presence can substantially affect the performance and reliability of the device. This article presents a high-performance piezoelectric micromachined ultrasonic transducer (PMUT) array with a stress-release (SR) structure. The PMUT array is a multilayer stacked structure that utilizes specific mechanical grooves etched into the device's active sensing layers to release residual stress. The piezoelectric layer of the PMUT structure is made of aluminum nitride (AlN). The PMUT array is developed on a silicon-on-insulator (SOI) platform, with dimensions of 4 x 4 mm. The array consists of 13 x 13 sensitive units, with each unit designed using a biomimetic honeycomb structure. The basic dimensions of the PMUT arrays with SR and conventional (CV) structures are identical. On the outer side of the SR structure's sensitive units, four mechanical grooves with a 120 degrees opening angle and a width of 20 mu m are etched. Electrical characteristics and transceiver performance tests were conducted on PMUTs with both structures. The results showed that the PMUTs with the SR structure exhibited higher mechanical quality factors and electromechanical coupling coefficients, with improvements of 37.6% and 9%, respectively, compared to the CV structure. Within the bandwidth range, the transceiver performance of the SR structure is 2 dB higher than that of the CV structure. These results validate the feasibility of the SR structure for achieving device stress matching, offering superior vibration and transceiver performance compared to the CV structure.

The long-term monitoring of respiratory status is crucial for the prevention and diagnosis of respiratory diseases. However, existing continuous respiratory monitoring devices are typically bulky and require either chest strapping or proximity to the nasal area, which compromises user comfort and may disrupt the monitoring process. To overcome these challenges, we have developed a flexible, attachable, lightweight, and miniaturized system designed for extended wear on the wrist. This system incorporates signal acquisition circuitry, a mobile client, and a deep neural network, facilitating long-term respiratory monitoring. Specifically, we fabricated a highly sensitive (11,847.24 kPa-1) flexible pressure sensor using a screen printing process, which is capable of functioning beyond 70,000 cycles. Additionally, we engineered a bidirectional long short-term memory (BiLSTM) neural network, enhanced with a residual module, to classify various respiratory states including slow, normal, fast, and simulated breathing. The system achieved a dataset classification accuracy exceeding 99.5%. We have successfully demonstrated a stable, cost-effective, and durable respiratory sensor system that can quantitatively collect and store respiratory data for individuals and groups. This system holds potential for everyday monitoring of physiological signals and healthcare applications.

Packaged temperature sensors exhibit significant thermal hysteresis effects, which directly impact their dynamic performance and accuracy during rapid temperature variations in marine environments. This article focuses on platinum resistance thermometers (PRTs), which are commonly used in oceanic applications, and a dynamic testing method was proposed that employs temperature step excitation within a fully liquid environment, along with a full range dynamic error compensation approach based on the fireworks algorithm (FWA). Initially, a dynamic testing system was developed, and its testing repeatability was verified. Subsequently, a sample database for PRTs at various temperature steps was created. By optimizing the fitness function, the FWA was utilized on the sample database during the iterative process to design a dynamic error compensation filter. The resulting compensation filter demonstrated enhanced universality across various temperature step sizes within the sensor measurement range. Through the filter's compensation, the rise time of the packaged PRT was reduced from an average of 477-121 ms within the measurement range. Furthermore, the dynamic response characteristics of the packaged PRT closely resembled those of the bare PRT. The dynamic testing method, which simulates heat transfer in real-world scenarios, in conjunction with the dynamic compensation method introduced in this article, can also be employed to achieve dynamic compensation for sensors operating under diverse testing principles.

The combination of pseudocapacitive electrodes with ionic liquid (IL) electrolytes demonstrates a significant synergistic effect in expanding the potential window of supercapacitors, thereby enhancing the energy density of the device. Mn3(HHTP)2, a metal-organic framework (MOF) with high-density redox-active sites and hierarchical porosity, serves as the electrode material paired with [EMIM][BF4] and [EMIM][TFSI] IL electrolytes. The ion size in [EMIM][TFSI] can be precisely aligned with the electrode pore size, thereby reducing interfacial resistance and enhancing ion accessibility. Optimizing the [EMIM][TFSI]/acetonitrile mass ratio to 4:6 achieves superior electrolyte properties, including an ionic conductivity of 50.4 mS cm-1 and viscosity of 5.24 mPa & sdot;s. This design extends operating potential from 8 V to 13 V, increasing energy density to 108.0 Wh kg-1, representing a 68.8 % improvement over baseline systems. The device retains 94.34 % capacitance after 2000 cycles at 8 V, with specific capacitances of 7.2 F g-1 at 8 V and 4.6 F g-1 at 13 V. These findings establish a new paradigm for interface engineering in high-voltage supercapacitors.

Conductivity sensing plays a crucial role in biochemical and industrial process monitoring, particularly in complex liquid environments such as fermentation systems. This study developed a monolithically integrated sensor based on microelectromechanical systems (MEMS) technology, which innovatively combines a concentric four-electrode conductivity sensor with a four-wire platinum resistance temperature detector (RTD). The sensor is designed to track fermentation progress by performing in situ, real-time monitoring of conductivity and temperature variations. Electric field simulations based on rigorous geometric modeling confirmed the establishment of a uniform sensing field between the current excitation electrodes, effectively confining the measurement region. This concentric ring electrode design successfully generated a uniform current density field between the two voltagesensing electrodes, thereby providing an ideal condition for accurate solution conductivity measurement. The sensor was fabricated on a BF33 glass substrate using standard MEMS processes, including photolithography, ion beam etching (IBE), and plasma-enhanced chemical vapor deposition (PECVD) of a SiO2 insulation layer, achieving high integration and batch manufacturability. Comprehensive performance characterization verified its excellent microstructural characteristics and electrochemical performance. The sensor demonstrated outstanding overall performance: a temperature measurement accuracy of +/- 0.3%, a conductivity measurement accuracy of +/- 2%; excellent long-term stability with a monthly drift of less than 0.2% for the temperature sensor and less than 3% for the conductivity sensor. A compensation model, established using the integrated temperature sensor, effectively eliminated the impact of temperature fluctuations on conductivity measurements. Ultimately, in a practical yogurt fermentation application, the conductivitytime profile obtained by this sensor showed close agreement with the trend measured by a pH sensor, successfully revealing the dynamic changes of key fermentation stages. This study not only validates the high reliability of the integrated sensor but also provides a solid foundation for its broad application in monitoring complex biological processes.

Self-powered broadband photodetectors (PDs) have garnered significant attention due to their extensive application potential, high precision, and multifunctionality. However, low responsivity, slow response times and narrowband optical response often limit their practical utility. This study presents a novel self-powered Ag2Se/ SiO2/Si heterojunction photodetector (PD) fabricated via magnetron sputtering technology. For the first time, by comparing the photoresponse of different structures, the control effect of the SiO2 layer on the change in Ag2Se pyrovoltage was discovered. The device exhibits fast response times, with a rise time of 5.01 ms and a fall time of 9.78 ms, demonstrating its capability for ultrafast photoresponse. Notably, the device demonstrates a broadband optical response that spans from the ultraviolet (330 nm) to near infrared (1550 nm) regions. Under zero bias voltage conditions and illuminated by an 808 nm laser, the PD demonstrates exceptional performance with a responsivity (Rv) of 2.727 V/W and detectivity (D*) of 3.409 x 1010 Jones. These results highlight the effectiveness of the Ag2Se/SiO2/Si heterojunction structure in achieving low power consumption, high optical responsivity, and self-powered detection, establishing it as a promising candidate for next-generation optoelectronic devices.