纳米光天线耦合增强型BeMgZnO基日盲探测器的制备及性能研究

Due to the advantages of simple process, filterless and matrix devices available, solar blind detector based on wide band gap semiconductors has been payed much attentions. However, low responsivity and low solar blind rejection ratio are two main obstacles for the application of semiconductor based solar blind detector. This project is concentrate on the investigation of wide BeMgZnO based solar blind detector to realize such goal. Firstly, lattice mismatch and thermal mismatch between the substrate and BeMgZnO layer are eliminated by using high quality ZnO substrate. High quality and bandgap (200 nm~280 nm) adjustable BeMgZnO alloy films will be prepared by using molecular beam epitaxy method (MBE). By using first principle calculations, electronic structure and phase stable mechanism of BeMgZnO will be also discussed. Secondly, MSM BeMgZnO based solar blind detectors are fabricated to investigating the influence factors of metal-semiconductor contact characteristics, including different work function metal, surface states, etc. Finally, we using AAO model to preparing nano-metal particle arrays on the surface of BeMgZnO solar blind detector or using EBL method to preparing metal nanorod array as nano-optical antenna. Combining with experimental and theoretical analysis, we will clarify the relationship between responsivity and the resonance wavelength (scattering cross section) of nanonano-optical antenna. With these solid cornerstones, high performance MSM BeMgZnO solar blind detector will have more chance.

基于宽禁带半导体的日盲探测器是一种军民两用型器件，它因工艺简单、无需滤光片及可制成面阵器件等优点而备受关注。但目前日盲探测器仍面临光响应度和日盲抑制比（峰值光响应度/280 nm处的光响应度）较低的问题。本课题围绕实现该目标的BeMgZnO基日盲探测器开展研究：首先，通过选择ZnO单晶作为衬底最大程度消除BeMgZnO外延层和衬底之间的晶格失配和热失配，获得高质量、能带在日盲区（200nm~280nm）大范围可调的六方相BeMgZnO合金薄膜；并结合第一性原理对BeMgZnO合金的电子结构等性质展开理论计算，阐清相结构的稳定机制。其次，在此基础上制备MSM型的BeMgZnO基日盲探测器，研究不同功函数的接触金属和表面态对金属-半导体接触特性的影响，获得稳定可控的金属-半导体接触。最后，制备金属纳米结构阵列作为光天线，利用等离子激元共振增强效应实现小尺寸、高性能的BeMgZnO基日盲探测器。

基于宽禁带半导体的日盲探测器是一种军民两用型器件，它因工艺简单、无需滤光片及可制成面阵器件等优点而备受关注。本项目利用分子束外延的方法制备了不同Be、Mg组份的四元BeMgZnO合金，通过改善缓冲层的技术，成功获得了高结晶质量、能带从近紫外到日盲区（200 nm~280 nm）连续可调的单一六方相BeMgZnO外延薄膜。结合理论研究，我们系统阐述了六方相结构稳定的物理机制。在材料的基础上，我们制备了MSM结构光电导型、肖特基结型和异质结型紫外探测器，实现了器件的截止响应波长连续可调，单一器件在日盲波段具有良好的响应。此外，我们还系统研究了ZnO的合金化对晶体结构和能带结构等的影响。研究发现Be掺杂引入了禁带间的局域激子态，该局域激子态参与了带间跃迁，大大地增加了共振拉曼信号的强度。本工作对实现高性能、小尺寸的BeMgZnO基紫外探测器的进一步应用打下了坚实的研究基础。