柔性ZnO压电电子学声表面波紫外光探测器研究

Flexible ZnO surface acoustic wave (SAW) ultraviolet (UV) photodetectors (PDs) have distinct advantages in practical applications, such as electronic skin and health monitoring. However, lots of efforts are still needed in the research area of their UV photodetection performances. In this proposal, based on the piezoelectric effect of ZnO semiconducting sensitive layer and naturally bendable properties of flexible SAW devices, a concept of flexible ZnO piezotronic SAW UV PD that integrates flexible ZnO SAW device and ZnO junction-based piezotronic device together is proposed. The dependence of externally applied strains on the acoustoelectric effect and UV photodetection performances are systematically and carefully investigated. The effects of externally applied strains on the frequency spectral characteristics of SAW are studied by fabricating ZnO junction-based piezotronic devices at the sensitive area of flexible ZnO SAW devices. The devices’ simulation models are built using multiphysics finite element analysis software, and then the dependence of externally applied strains on the frequency spectral characteristics of SAW is derived via combining the simulation results and the theory of acoustoelectric effect. Finally, the effects of the devices’ parameters and externally applied strains on the flexible ZnO piezotronic SAW UV PDs’ performances are optimized theoretically and high performance flexible ZnO piezotronic SAW UV PDs are realized experimentally. This proposal has great significance in revealing the dependence of externally applied strains on the performance of flexible SAW UV PDs and pushing them into practical applications.

柔性ZnO声表面波紫外光探测器在电子皮肤、人体健康监测等方面具有显著优势，但其紫外探测性能研究仍有待突破。本项目基于ZnO半导体敏感膜的压电特性和柔性声表面波器件的可弯曲特性，提出将柔性ZnO声表面波器件与ZnO压电电子学器件集成，实现一种新型柔性ZnO压电电子学声表面波紫外光探测器，重点研究外加应变对声电效应及紫外探测性能的影响规律。在柔性ZnO声表面波器件敏感膜区域制备ZnO压电电子学器件，研究外加应变对声表面波频谱特性的影响规律；利用多物理场有限元仿真软件建立集成结构器件模型，结合声电效应理论进行仿真计算，推导声表面波频谱特性受外加应变影响的理论公式；系统研究柔性ZnO压电电子学声表面波紫外光探测器的响应特性规律，获得高性能的柔性ZnO压电电子学声表面波紫外光探测器。本项目对揭示柔性声表面波紫外光探测器受外加应变的影响规律及推进其实用化具有重要研究意义和应用价值。

伴随着信息化社会、物联网与人工智能的高速发展，柔性紫外光探测器也逐渐成为研究热点而被研究人员所广泛关注。柔性声表面波紫外光探测器具有抗电磁干扰能力强、易于实现无线信号传输、与半导体制造工艺相兼容等优点，而其紫外光响应仍有待于进一步增强。本项目提出将柔性ZnO声表面波器件与垂直结构ZnO结型器件进行集成，利用ZnO的压电效应与半导体特性，通过引入外加应变实现对声表面波器件紫外光响应的可控调制和增强。本项目主要取得了以下几方面创新性成果：（1）系统地研究了垂直结构Si/ZnO异质结器件的光响应特性受外加应变产生的压电电荷的调制作用，揭示了Si/ZnO异质结器件中压电电荷调制作用的底层物理机制，调制增幅最高可达约3倍；（2）系统地研究了ZnO层载流子浓度对压电电荷调制作用的影响，结果表明只有当ZnO层的掺杂浓度适中为1015-1017 cm-3时，压电电荷调制作用最明显；（3）系统地研究了三明治结构ZnO基异质结器件的光响应特性受压电电荷的调制规律，将ZnO压电半导体作为夹层有效提高了压电电荷的利用率，大大提高了压电电荷对异质结器件光响应特性的调制幅度，在p-i-n结器件中可达50倍；（4）建立了垂直结构ZnO结型器件中ZnO内载流子浓度分布和薄层电导率受压电电荷调制的理论模型并推导获得了解析表达式，通过多物理场有限元模拟仿真进行了验证，研究了外加应变对柔性声表面波器件中心频率的调制作用，将垂直结构ZnO结型器件中ZnO薄层电导率以及柔性声表面波器件中心频率受外加应变的调制作用结合，揭示了外加应变对柔性ZnO压电电子学声表面波紫外光探测器光响应的调控机制并给出了解析表达式。本项目为柔性声表面波紫外光探测器的性能优化、高性能微波射频紫外光探测器的研发提供了实验和理论基础，具有重要的科学意义和潜在的应用价值。