1 中国科学院 上海微系统与信息技术研究所 信息功能材料国家重点实验室，上海 200050
2 中国科学院大学，北京 100049
3 上海集成电路材料研究院，上海 200050
该文基于掺钪AlN薄膜制备了高次谐波体声波谐振器(HBAR)，研究了钪(Sc)掺杂浓度对AlN压电薄膜材料特性及器件性能的影响。研究表明，当掺入Sc的摩尔分数从0增加到25%时，压电应力系数e33增加、刚度CD33下降，导致Al1-xScxN压电薄膜的机电耦合系数k2t从5, 6%提升至15, 8%，从而使HBAR器件的有效机电耦合系数(k2eff)提升了3倍。同时，当Sc掺杂摩尔分数达25%时，Al1-xScxN(x为Sc掺杂摩尔分数)压电薄膜的声速下降13%，声学损耗提高，导致HBAR器件的谐振频率和品质因数降低。
高次谐波体声波谐振器(HBAR) 压电薄膜 掺钪AlN 机电耦合系数 high-overtone bulk acoustic resonator(HBAR) AlN AlN piezoelectric thin film aluminum scandium nitride electromechanical coupling coefficient
1 南京理工大学自动化学院，江苏 南京 210094
2 中建八局第三建设有限公司，江苏 南京 210023
立体匹配是三维重建技术中的关键步骤，针对局部立体匹配算法在弱纹理区域、深度不连续区域匹配效果差，且容易受到噪声干扰的问题，提出了一种基于多特征融合的局部立体匹配算法。对传统的Census变换进行改进，使其对噪声具有更强的鲁棒性，并将其与颜色特征、梯度特征相融合进行代价计算；采用多尺度下的引导滤波算法进行代价聚合，并通过视差计算与优化得到视差图。在Middlebury数据集上的实验结果表明，所提算法抗噪能力强，且与当前较为优秀的局部立体匹配算法相比，匹配精度有了进一步提升。
图像处理 立体匹配 Census变换 多特征融合 引导滤波 激光与光电子学进展
2022, 59(8): 0810011
Author Affiliations
Abstract
1 College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, China
2 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
Strain regulation as an effective way to enhance the photoelectric properties of two-dimensional (2D) transition metal dichalcogenides has been widely employed to improve the performance of photovoltaic devices. In this work, tensile strain was introduced in multilayer grown on GaN by depositing 3 nm of on the surface. The temperature-dependent Raman spectrum shows that the thermal stability of is improved by . Theoretical simulations confirmed the existence of tensile strain on covered with , and the bandgap and electron effective mass of six layers of decreased due to tensile strain, which resulted in an increase of electron mobility. Due to the tensile strain effect, the photodetector with the stress liner achieved better performance under the illumination of 365 nm wavelength, including a higher responsivity of 24.6 A/W, photoconductive gain of 520, and external quantum efficiency of 8381%, which are more than twice the corresponding values of photodetectors without . Our work provides an effective technical way for improving the performance of 2D material photodetectors.
Photonics Research
2020, 8(6): 06000799
中国矿业大学信息与控制工程学院, 江苏 徐州 221116
提出一种参数自适应的在线字典学习图像超分辨率重建算法。在经典的稀疏表示算法框架下,运用在线字典学习方法来提高字典学习的精度。通过参数自适应方法灵活调整稀疏重建阶段的正则化参数,并依据每个图像块的特点自适应确定正则化参数,以此克服人为设定参数的单一性和非最佳参数值的缺点。实验结果表明,与传统算法相比,所提算法可有效降低测试图像对训练图像集的依赖程度,同时克服图像在重建过程中存在的局部模糊或失真,进一步提高重建图像的质量。
机器视觉 图像重建 超分辨率 在线字典学习 正则化参数 自适应 激光与光电子学进展
2020, 57(6): 061505
1 中国矿业大学信息与控制工程学院, 江苏徐州 221116
2 安徽省皖北煤电集团有限责任公司信息中心, 安徽宿州 234000
针对基于 LBP的许多改进方法需要提前训练, 对旋转和照明变化鲁棒性较差的特点, 本文通过融合 CLBP和图像表面的局部几何不变特征提出了一种新的纹理分类方法。该算法首先计算图像表面的局部几何不变特征, 然后对其进行量化和编码。其次, 再将编码结果与 CLBP直方图进行融合。本文提出的算法能够同时提取图像的宏观和微观特征, 且具有不明显增加特征维度, 无需提前训练, 对图像的旋转和光照变化保持不变的特点。在两个标准纹理数据库上进行实验验证, 结果表明, 本文算法与其它算法相比在分类精度和鲁棒性上都有明显的提高。
纹理分类 局部几何不变特征 LBP LBP CLBP CLBP texture classification local geometric invariant features
1 中国矿业大学信息与控制工程学院, 江苏 徐州 221116
2 皖北煤电集团有限责任公司, 安徽 宿州 234000
针对局部立体匹配算法中边缘区域易造成误匹配的问题,提出一种基于边缘加权的跨尺度局部立体匹配算法。在代价计算阶段,根据边缘点的数量和结构信息提出一种边缘相似度测量方法,并对满足约束条件的点进行两种策略的“奖励”加权,以提高目标图和参考图中对应点的辨识度;在代价聚合阶段,引入多尺度模型,并采用引导滤波进行聚合;通过视差计算、视差精化得到最终视差图。在Middlebury立体视觉测试平台下对4组标准立体图像对和27组扩展立体图像对进行测试。实验结果显示,在未加入任何精化步骤的情况下,非遮挡区域的平均误匹配率为7.88%,说明本文算法有效改善了边缘区域的匹配精度。
机器视觉 立体匹配 跨尺度 边缘检测 引导滤波 激光与光电子学进展
2019, 56(21): 211504
Author Affiliations
Abstract
1 State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore
4 Shenzhen Castle Security Technology Co., Ltd., Shenzhen 518000, China
5 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
6 e-mail: liuxinke@ciomp.ac.cn
7 e-mail: lidb@ciomp.ac.cn
With the increasing demand for high integration and multi-color photodetection for both military and civilian applications, the research of multi-wavelength detectors has become a new research hotspot. However, current research has been mainly in visible dual- or multi-wavelength detectors, while integration of both visible light and ultraviolet (UV) dual-wavelength detectors has rarely been studied. In this work, large-scale and high-quality monolayer was grown by the chemical vapor deposition method on transparent free-standing GaN substrate. Monolithic integration of -based visible detectors and GaN-based UV detectors was demonstrated using common semiconductor fabrication technologies such as photolithography, argon plasma etching, and metal deposition. High performance of a 280 nm and 405 nm dual-wavelength photodetector was realized. The responsivity of the UV detector reached 172.12 A/W, while that of the visible detector reached 17.5 A/W. Meanwhile, both photodetectors achieved high photocurrent gain, high external quantum efficiency, high normalized detection rate, and low noise equivalent power. Our study extends the future application of dual-wavelength detectors for image sensing and optical communication.
Photonics Research
2019, 7(10): 10001127
