Exploring Nanoscale Perovskite Materials for Next‑Generation Photodetectors:A Comprehensive Review and Future Directions

The rapid advancement of nanotechnology has sparked much interest in applying nanoscale perovskite materials for photodetection applications.These materials are promising candidates for next-generation photodetectors(PDs)due to their unique optoelectronic properties and flexible synthesis routes.This review explores the approaches used in the development and use of optoelectronic devices made of different nanoscale perovskite architectures,including quantum dots,nanosheets,nanorods,nanowires,and nanocrystals.Through a thorough analysis of recent literature,the review also addresses common issues like the mechanisms underlying the degradation of perovskite PDs and offers perspectives on potential solutions to improve stability and scalability that impede widespread implementation.In addition,it highlights that photodetection encompasses the detection of light fields in dimensions other than light intensity and suggests potential avenues for future research to overcome these obstacles and fully realize the potential of nanoscale perovskite materials in state-of-the-art photodetection systems.This review provides a comprehensive overview of nanoscale perovskite PDs and guides future research efforts towards improved performance and wider applicability,making it a valuable resource for researchers.

M_(4)X_(3) MXenes:Application in Energy Storage Devices

MXene has garnered widespread recognition in the scientific com-munity due to its remarkable properties,including excellent thermal stability,high conductivity,good hydrophilicity and dispersibility,easy processability,tunable surface properties,and admirable flexibility.MXenes have been categorized into different families based on the number of M and X layers in M_(n+1)X_(n),such as M_(2)X,M_(3)X_(2),M_(4)X_(3),and,recently,M_(5)X_(4).Among these families,M_(2)X and M_(3)X_(2),par-ticularly Ti_(3)C_(2),have been greatly explored while limited studies have been given to M_(5)X_(4)MXene synthesis.Meanwhile,studies on the M_(4)X_(3)MXene family have developed recently,hence,demanding a compilation of evaluated studies.Herein,this review provides a systematic overview of the latest advancements in M_(4)X_(3)MXenes,focusing on their properties and applications in energy storage devices.The objective of this review is to provide guidance to researchers on fostering M_(4)X_(3)MXene-based nanomaterials,not only for energy storage devices but also for broader applications.

Tunneling via surface dislocation in W/β-Ga_(2)O_(3) Schottky barrier diodes

In this work,W/β-Ga_(2)O_(3)Schottky barrier diodes,prepared using a confined magnetic field-based sputtering method,were analyzed at different operation temperatures.Firstly,Schottky barrier height increased with increasing temperature from 100 to 300 K and reached 1.03 eV at room temperature.The ideality factor decreased with increasing temperature and it was higher than 2 at 100 K.This apparent high value was related to the tunneling effect.Secondly,the series and on-resistances decreased with increasing operation temperature.Finally,the interfacial dislocation was extracted from the tunneling current.A high dislocation density was found,which indicates the domination of tunneling through dislocation in the transport mecha-nism.These findings are evidently helpful in designing better performance devices.

Highly Transparent and Flexible All-Nanofiber-Based Piezocomposite Containing BaTiO_(3)-Embedded P(VDF-TrFE)Nanofibers for Harvesting and Monitoring Human Kinetic Movements

We developed kinetic energy-harvestable and kinetic movement-detectable piezoelectric nanogenerators(PENGs)consisting of piezoelectric nanofiber(NF)mats and metal-electroplated microfiber(MF)electrodes using electrospinning and electroplating methods.Percolative non-woven structure and high flexibility of the NF mats and MF electrodes allowed us to achieve highly transparent and flexible piezocomposites.A viscoelastic solution,mixed with P(VDF-TrFE)and BaTiO_(3),was electrospun into piezoelectric NFs with a piezoelectric coefficient d33 of 21.2 pC/N.In addition,the combination of electrospinning and elec-troplating techniques enabled the fabrication of Ni-plated MF-based transparent conductive electrodes(TCEs),contributing to the high transparency of the resulting piezocomposite.The energy-harvesting efficiencies of the BaTiO_(3)-embedded NF-based PENGs with transmittances of 86%and 80%were 200 and 240 V/MPa,respectively,marking the highest values in their class.Moreover,the output voltage driven by the coupling effect of piezoelectricity and triboelectricity during finger tapping was 25.7 V.These highly efficient energy-harvesting performances,along with the transparent and flexible features of the PENGs,hold great promise for body-attachable energy-harvesting and sensing devices,as demonstrated in this study.

Soft,full Wheatstone bridge 3D pressure sensors for cardiovascular monitoring

Variations in parameters associated with the ambient environment can introduce noise in soft,body-worn sensors.For example,many piezoresistive pressure sensors exhibit a high degree of sensitivity to fluctuations in temperature,thereby requiring active compensation strategies.The research presented here addresses this challenge with a multilayered 3D microsystem design that integrates four piezoresistive sensors in a full-Wheatstone bridge configuration.An optimized layout of the sensors relative to the neutral mechanical plane leads to both an insensitivity to temperature and an increased sensitivity to pressure,relative to previously reported devices that rely on similar operating principles.Integrating this 3D pressure sensor into a soft,flexible electronics platform yields a system capable of real-time,wireless measurements from the surface of the skin.Placement above the radial and carotid arteries yields high-quality waveforms associated with pulsatile blood flow,with quantitative correlations to blood pressure.The results establish the materials and engineering aspects of a technology with broad potential in remote health monitoring.

RGB Color-Discriminable Photonic Synapse for Neuromorphic Vision System

To emulate the functionality of the human retina and achieve a neuromorphic visual system,the development of a photonic synapse capable of multispectral color discrimination is of paramount importance.However,attaining robust color discrimination across a wide intensity range,even irrespective of medium limitations in the channel layer,poses a significant challenge.Here,we propose an approach that can bestow the color-discriminating synaptic functionality upon a three-terminal transistor flash memory even with enhanced discriminating capabilities.By incorporating the strong induced dipole moment effect at the excitation,modulated by the wavelength of the incident light,into the floating gate,we achieve outstanding RGB color-discriminating synaptic functionality within a remarkable intensity range spanning from 0.05 to 40 mW cm^(-2).This approach is not restricted to a specific medium in the channel layer,thereby enhancing its applicability.The effectiveness of this color-discriminating synaptic functionality is demonstrated through visual pre-processing of a photonic synapse array,involving the differentiation of RGB channels and the enhancement of image contrast with noise reduction.Consequently,a convolutional neural network can achieve an impressive inference accuracy of over 94%for Canadian-Institute-For-Advanced-Research-10 colorful image recognition task after the pre-processing.Our proposed approach offers a promising solution for achieving robust and versatile RGB color discrimination in photonic synapses,enabling significant advancements in artificial visual systems.

Programmable directional color dynamics using plasmonics

Adaptive multicolor filters have emerged as key components for ensuring color accuracy and resolution in outdoor visual devices.However,the current state of this technology is still in its infancy and largely reliant on liquid crystal devices that require high voltage and bulky structural designs.Here,we present a multicolor nanofilter consisting of multilayered‘active’plasmonic nanocomposites,wherein metallic nanoparticles are embedded within a conductive polymer nanofilm.These nanocomposites are fabricated with a total thickness below 100 nm using a‘lithography-free’method at the wafer level,and they inherently exhibit three prominent optical modes,accompanying scattering phenomena that produce distinct dichroic reflection and transmission colors.Here,a pivotal achievement is that all these colors are electrically manipulated with an applied external voltage of less than 1 V with 3.5 s of switching speed,encompassing the entire visible spectrum.Furthermore,this electrically programmable multicolor function enables the effective and dynamic modulation of the color temperature of white light across the warm-to-cool spectrum(3250 K-6250 K).This transformative capability is exceptionally valuable for enhancing the performance of outdoor optical devices that are independent of factors such as the sun’s elevation and prevailing weather conditions.

Autonomous self-healing in a stretchable polybutadiene-based urethane and eutectic gallium indium conductive composite

In the burgeoning field of wearable electronics,flexible and durable conductors that can maintain consistent electrical properties under various conditions are critically needed.This research introduces a novel composite material comprising eutectic gallium-indium(EGaIn)and a polybutadiene-based urethane(PBU)specifically designed to address this challenge.EGaIn,renowned for its superior conductivity due to its liquid state at room temperature,is strategically combined with PBU,which offers inherent flexibility and remarkable self-healing capabilities derived from reversible Diels–Alder reactions.Additionally,the composite maintains exceptional electrical resistance stability,withstanding mechanical strains up to 135%without compromising performance.The material’s self-healing capability is attributed to the autonomous mending properties of EGaIn and the reversible Diels–Alder reactions in the PBU matrix.The result is an efficient restoration of the composite’s original properties upon incurring damage.Furthermore,the composite’s adaptability is showcased through its printability,allowing for precise patterning conducive to custom-designed wearable devices.

用于制备具有超光滑表面异质集成4英寸硅基砷化镓薄膜的高效离子剥离技术

在Si衬底上将单晶GaAs薄膜与其进行异质集成有望为硅基光电集成提供新的材料平台.本文基于对GaAs材料剥离机理的分析阐述,优化了GaAs薄膜转移工艺的离子注入条件.结果表明,相比于He离子单独注入,由于较小的热预算和注入后相对更低的缺陷密度,He/H离子共注入对于GaAs薄膜转移更高效.以Al2O3为键合介质层,通过优化的离子剥离技术成功地将4英寸GaAs薄膜转移到Si(100)衬底上.探索了包括化学机械抛光、臭氧辐照氧化和KOH清洗的表面处理工艺,以将转移后GaAs薄膜的表面质量提高到可以高质量外延的水平.在400℃退火1 h后,转移的GaAs薄膜单晶质量进一步提高,X射线摇摆曲线的半峰全宽仅为89.03 arcsec.

Si-based InGaAs photodetectors on heterogeneous integrated substrate

In this paper,InGaAs p-i-n photodetectors(PDs)on an InP/SiO2/Si(InPOI)substrate fabricated by ion-slicing technology are demonstrated and compared with the identical device on a commercial InP substrate.The quality of epitaxial layers on the InPOI substrate is similar to that on the InP substrate.The photo responsivities of both devices measured at 1.55μm are comparable,which are about 0.808-0.828 A W^(-1).Although the dark current of PD on the InPOI substrate is twice as high as that of PD on the InP substrate at 300 K,the peak detectivities of both PDs are comparable.In general,the overall performance of the InPOI-based PD is comparable to the InP-based PD,demonstrating that the ion-slicing technology is a promising route to enable the highquality Si-based InP platform for the full photonic integration on a Si substrate.