Growth of high quality InSb thin films on GaAs substrates by molecular beam epitaxy method with AlInSb/GaSb as compound buffer layers

A series of In Sb thin films were grown on Ga As substrates by molecular beam epitaxy(MBE).Ga Sb/Al In Sb is used as a compound buffer layer to release the strain caused by the lattice mismatch between the substrate and the epitaxial layer,so as to reduce the system defects.At the same time,the influence of different interface structures of Al In Sb on the surface morphology of buffer layer is explored.The propagation mechanism of defects with the growth of buffer layer is compared and analyzed.The relationship between the quality of In Sb thin films and the structure of buffer layer is summarized.Finally,the growth of high quality In Sb thin films is realized.

Fast UV-vis-NIR photoresponse of self-oriented F_(16)CuPc nanoribbons

Controlling the vapor-deposited nanoribbons to grow along a consistent orientation will enable the desired in situ integration of functional devices,representing a major technological advance compared to post-growth processing strategies.In this work,ntype F_(16)CuPc molecules are self-assembled into horizontally-oriented nanoribbons with a consistent growth axis after creating periodic hydrophobic nanogrooves on a sapphire surface.Consequently,electrodes are deposited directly on the growth substrate to enable in situ fabrication of photodetectors.Depending on the deposited electrodes,these horizontally-oriented nanoribbons are connected to form a monolithic photodetector with a large sensing area or an on-chip array of photodetectors with multiple detector units.This in situ integration strategy avoids potential structural damage and contamination from impurities associated with post-growth processing steps.Therefore,the vapor-deposited nanoribbons can retain their high quality during the device manufacturing process,which contributes to performance improvement.As a result,the in-situ integrated F_(16)CuPc photodetectors exhibit a sensitive response in the ultraviolet-visible-near-infrared(UV-vis-NIR)region.The response time is on the order of tens of milliseconds,the fastest record ever for the F_(16)CuPc-based photodetectors.Furthermore,statistics from an array of 6×6 photodetectors show little variation in their sensitivity and response time,and hence this in situ fabrication scheme will contribute to the implementation of on-chip integrated photodetectors with consistent performance based on bottom-up nanoribbons.Overall,this self-oriented growth provides a versatile option to achieve desired in-situ integrated functional devices based on bottom-up nanoribbons.

A flexible and high temperature tolerant strain sensor of La0.7Sr0.3MnO3/Mica

Flexible sensors have been widely investigated due to their broad application prospects in various flexible electronics.However,most of the presently studied flexible sensors are only suitable for working at room temperature,and their applications at high or low temperatures are still a big challenge.In this work,we present a multimodal flexible sensor based on functional oxide La0.7Sr0.3MnO3(LSMO)thin film deposited on mica substrate.As a strain sensor,it shows excellent sensitivity to mechanical bending and high bending durability(up to 3600 cycles).Moreover,the LSMO/Mica sensor also shows a sensitive response to the magnetic field,implying its multimodal sensing ability.Most importantly,it can work in a wide temperature range from extreme low temperature down to 20K to high temperature up to 773 K.The flexible sensor based on the flexible LSMO/mica hetero-structure shows great potential applications for flexible electronics using at extreme temperature environment in the future.

Neural network-based surrogate model for inverse design of metasurfaces

Metasurfaces composed of spatially arranged ultrathin subwavelength elements are promising photonic devices for manipulating optical wavefronts,with potential applications in holography,metalens,and multiplexing communications.Finding microstructures that meet light modulation requirements is always a challenge in designing metasurfaces,where parameter sweep,gradient-based inverse design,and topology optimization are the most commonly used design methods in which the massive electromagnetic iterations require the design computational cost and are sometimes prohibitive.Herein,we propose a fast inverse design method that combines a physicsbased neural network surrogate model(NNSM)with an optimization algorithm.The NNSM,which can generate an accurate electromagnetic response from the geometric topologies of the meta-atoms,is constructed for electromagnetic iterations,and the optimization algorithm is used to search for the on-demand meta-atoms from the phase library established by the NNSM to realize an inverse design.This method addresses two important problems in metasurface design:fast and accurate electromagnetic wave phase prediction and inverse design through a single phase-shift value.As a proof-of-concept,we designed an orbital angular momentum(de)multiplexer based on a phase-type metasurface,and 200 Gbit/s quadrature-phase shift-keying signals were successfully transmitted with a bit error rate approaching 1.67×10^(-6).Because the design is mainly based on an optimization algorithm,it can address the“one-to-many”inverse problem in other micro/nano devices such as integrated photonic circuits,waveguides,and nano-antennas.

HfO_(2)铁电薄膜基MFIS存储结构中的高κ介电晶籽层效应研究:铁电正交相生长和界面电荷注入抑制

HfO_(2)基材料铁电场效应晶体管(FeFET)商业化应用面临的一个重要挑战是其疲劳特性差.本文提出,在基于金属-铁电-绝缘层-半导体(MFIS)栅叠层结构的FeFET中研发合适的高κ界面晶籽层(SL)以大幅度提升其疲劳性能.我们在ZrO_(2),HfO_(2),(HfO_(2))0.75(Al_(2)O_(3))0.25(HAO)和Al_(2)O_(3)等典型的高κ介电SL上制备了Hf_(0.5)Zr_(0.5)O_(2)(HZO)铁电薄膜,系统研究了HZO薄膜的微观结构、铁电性及其MFIS器件的存储特性.首先,揭示了HZO薄膜中铁电正交相的形核和生长不仅受高κ介电SL表面能的影响,而且其微观结构对HZO中正交相的形成也起到重要作用.其次,澄清了高κ介电晶籽层对MFIS结构存储特性的影响,通过精确计算的MFIS结构的界面层电场,对MFIS结构的存储特性做出了合理解释.最后,基于HAO的高κSL的MFIS器件实现了铁电极化和界面电荷注入之间的合理优化,并且获得了较大铁电存储窗口(>1.0 V),出色的保持特性(>1.6×104s)和疲劳特性(>105).本文为未来解决HfO_(2)基Fe FET的疲劳问题提供了有价值的思路,为在介电SL上生长HfO_(2)铁电薄膜的其他高性能电子器件的开发提供了参考.

Orbital angular momentum mode logical operation using optical diffractive neural network

Optical logical operations demonstrate the key role of optical digital computing,which can perform general-purpose calculations and possess fast processing speed,low crosstalk,and high throughput.The logic states usually refer to linear momentums that are distinguished by intensity distributions,which blur the discrimination boundary and limit its sustainable applications.Here,we introduce orbital angular momentum(OAM)mode logical operations performed by optical diffractive neural networks(ODNNs).Using the OAM mode as a logic state not only can improve the parallel processing ability but also enhance the logic distinction and robustness of logical gates owing to the mode infinity and orthogonality.ODNN combining scalar diffraction theory and deep learning technology is designed to independently manipulate the mode and spatial position of multiple OAM modes,which allows for complex multilight modulation functions to respond to logic inputs.We show that few-layer ODNNs successfully implement the logical operations of AND,OR,NOT,NAND,and NOR in simulations.The logic units of XNOR and XOR are obtained by cascading the basic logical gates of AND,OR,and NOT,which can further constitute logical half-adder gates.Our demonstrations may provide a new avenue for optical logical operations and are expected to promote the practical application of optical digital computing.

厚度依赖的聚合物稳定胆甾相液晶的电控红外反射器件（英文）

本文报道了基于聚合物胆甾相液晶的、可电场调控的红外反射器件的制备,并系统研究了器件厚度对器件性能的影响.即施加直流电场后,厚度较小的器件的反射带宽仅发生红移;厚度较大的器件的反射带宽增宽.这种现象是由于不同厚度的胆甾相液晶薄膜中不同的螺距梯度导致的.本工作的研究结果表明在制备基于聚合物胆甾相液晶的电控红外反射器件时,厚度是决定反射性能的重要因素.由于该红外反射器件具有较快的响应时间和较好的工作稳定性,在建筑和汽车等的节能窗领域有较好的应用前景.