基于量子态工程调控的LSP增强型日盲紫外光电探测器及机理研究

In this program, we aim to intensively study the critical influences of the localized near-field enhancement and the hot-electron emission in the deep-ultraviolet (deep-UV) photodetectors, which is based on quantum state engineering by using effective dielectric theory combined with FDTD simulations. The fundamental coupling interactions between the localized surface plasmon (LSP) polarization and exciton from interband transitions will be explored and discussed, in order to understand the underlying mechanism of the enhanced absorption efficiency from exciton. Experimentally, based on the ultra-short period AlN/GaN superlattices by precisely growth technology by modulating the thickness of the atomic layers, the vacuum electron-beam deposition and nanosphere lithography will be implemented to fabricate large scale direct-contact aluminum, rhodium and aluminum/rhodium nanostructure arrays with controllable size, shape and density. Furthermore, by means of standard processes, the LSP-enhanced deep-UV photodetectors by quantum state engineering will be fabricated. In this way, these nanoparticle arrays can couple with the deep-UV light and generate LSP. The excited LSP will enhance the exciton absorption efficiency from interband quantum levels, which will remarkably enhance the external quantum efficiency of the deep-UV photodetectors based on interband quantum energy levels. This study will propose new possibilities and prospects of easily controlling the deep-UV light, as well as important guiding significance for applications of such new structures of deep-UV photodetectors.

本项目拟利用有效介电理论结合FDTD模拟手段，从理论层面深入研究金属局域近场增强效应及热电子发射效应在以量子态工程调控为基础的光电探测器中的关键作用，了解并探讨局域等离极化激元（LSP）与量子能级间激子运动的相互关系及影响规律，以期建立等离极化激元如何增强量子态工程调控下激子吸收效率的物理机制。实验上，以本研究组所掌握的原子层可控外延技术生长超短周期AlN/GaN超晶格为基础，运用真空电子束沉积法，结合纳米球刻蚀技术制备形成与超晶格基底进行能量耦合且尺寸、形状及密度可调控的金属纳米阵列。进一步地，通过微加工工艺制备基于超短周期AlN/GaN超晶格的LSP增强型日盲光电探测器。激发的LSP可增强量子能级间的激子吸收效率，显著提高器件的外量子效率，从而为更好地实现调控光、操纵光提供新的可能性，并在推进日盲紫外量子态调控的光电子器件应用方面有重要的指导意义。

本项目采用有效介电理论结合FDTD仿真模拟手段，从理论层面深入地探索金属纳米颗粒阵列形成的局域等离极化激元（LSP）与界面之间的干涉、共振及耦合行为，通过改变金属材料的种类和几何形态及光入射方向等来调控LSP共振的线宽和强度，在理论上建立了Fano共振的类强耦合物理模型；观测到所构建的包含金属纳米颗粒阵列的多层薄膜复合体系在极短腔长的条件下，波长约250nm处的光吸收率提高超过80%，吸收带宽压缩约一半以上，与理论预期相一致。另一方面，以调控晶体生长的化学势场为手段，采用第一性原理模拟了不同原子反应单体在晶体生长表面的化学势，揭示了反应单体随生长氛围变化的规律和机制；以理论计算为导向，通过设计瞬间改变生长氛围的时序方式，运用MOVPE技术外延生长出完全应变任意分子层数组合的超短周期AlN/GaN超晶格，所生长的超短周期超晶格具有可薄至单个分子层量级清晰可辨的陡峭异质界面，实现了吸附单体的一致性和原子级表面平整度。同时发展了微模板调控的自组装纳米球制备工艺，可完成大面积、均匀有序、尺寸和周期可调的金属铑纳米阵列的制备，在上述超短周期超晶格基底上构筑特定尺寸、形貌及密度的金属铑纳米结构体系，实现对日盲紫外波段范围内光吸收的有效调控。此外，开展光腔增强型量子能级间激子极化激元的研究，形成一种精细的微纳米尺度图形化制作技术，制备多维度光学微腔并实现了强局域情况的激子极化激元，为更好地实现调控光和操纵光提供新的可能性。

内容获取失败，请点击重试