氧化锌紫外纳米激光器的设计与模式调控

Surface plasmon (SP) creates an ideal approach to break through so-called optical diffraction limit and further construct nano-sized laser. However, some critical issues are still in challenge, such as mode control and single-mode operation, short-wavelength response, coupling mechanism，and electrically pumped nanolaser design, especially. In this project, SP-coupled ZnO whispering-gallery mode (WGM) microcavities will be designed and fabricated. In this case, both WGM optic field and SP wave are confined near the cavity surface and provide a favorable physical space for their coupling, while ZnO will compensate efficiently the SP response in short wavelength based on its superior gain in UV region. The flexible design of the resonant microcavities will be carried out based on the unique structure of ZnO nanocombs. The lasing modes will be controlled through the variation of the individual ZnO nanorod (comb teeth) and Vernier coupling between the adjacent nanorods with wedge-shaped gap. Metals will be introduced on the microcavity surface or inter-cavities gap to improve the lasing performance and adjust SPP coupling behavior. A p-type graphene/conductive polymer complex buffer layer will be designed and inserted in the hertojuctional nano-ZnO/p-GaN interface to satisfy the totally internal reflection, increase the hole injection, and improve the heat release. A series of analysis, including pulse electric field driven transient photo-capacitance or photo-current response, transient optical spectra, low temperature technology, and high-resolution micro-spectra will be employed to investigate the SP/semiconductor coupling mechanism, systematically. It is expected to draw a general physical model for SPP coupled semiconductor system in theory and realize a single-mode nanolaser working at short wavelength region in experiment, and further support the novel nanodevices design and photoelectric and photonic integration for their potential application in communication, sensing, and biomedical areas.

表面等离激元（SP）耦合的半导体微腔是突破衍射极限，实现纳米激光器的理想途径，但现有研究对纳米微腔中激光模式调控、短波响应、耦合机理等重要问题均缺乏深刻认识，电泵浦激光器更是缺乏有效的构建方案。本项目将充分利用回音壁模（WGM）微腔光场和SP波在界面附近耦合的物理优势，用ZnO为SP的短波响应提供高效增益补偿；基于ZnO纳米梳的独特结构，调变单个微腔尺度或腔间耦合的游标效应，实现模式结构的灵活调控，并结合金属SP，实现和提高单模激光性能；基于ZnO/p-GaN异质结构，设计p-型石墨烯/导电聚合物复合界面过渡层，以简便的方法满足内壁全反射条件，提高空穴注入能力，改善散热性能；通过对SP材料与增益介质的同步激发，结合瞬态光电特性探测、单粒子光谱、变温等技术，深刻揭示SP/半导体耦合机理，为新型纳米器件构建、光电及光子集成的推进及其在通信、传感、生物医学等领域的应用提供重要的科学依据与技术参考

面向众多半导体科学家关注的紫外纳米激光这一国际性难题，我们紧密围绕计划书拟定的研究内容与目标，开创性地将高增益回音壁（WGM）微腔引入异质结电泵浦器件之中，获得了稳定激光模式的电泵浦激光，集成了表面等离激元与WGM微腔效应极大提升了激光输出性能，并进一步发展了灵活调控激光模式的技术方法，实现了亚波长尺度紫外纳米激光器。从新型半导体纳米激光器的设计，到短波微腔激光的性能提升，再到面向应用的单模调控等一系列研究中取得了重要创新成果。相关研究成果已在Nano Energy，Adv. Opt. Mater.，Laser.Photonics Rev.，Nano Res.，《科学通报》等国内外重要学术刊物上发表论文54篇, 其中多个成果被Laser.Photonics Rev.，ACS Appl. Mater.Interface，J. Mater. Chem. C，Nanoscale等期刊作封面报道，并申请发明专利15项（授权专利7项,国际专利1项）。项目执行期间，培养了2名博士后出站，12名博士和13名硕士研究生毕业并获得学位。主要的进展与创新成果列举如下： .1）将表面等离激元引入到WGM微腔表面，充分利用了两者空间上高度局域的物理优势，协同诱导强烈的近场增强效应，显著提升了微腔激光的性能，揭示了直接能量共振耦合和局域表面等离激共振辅助电子转移两种不同的发光增强机理。.2）设计了不同金属/半导体结构的等离激元纳米激光器，从理论和实验上对等离激元激光行为进行了深入探讨，揭示了表面等离激元和半导体激子的耦合机制。.3）发展了损耗/增益控制、游标效应、电光调制等静态与动态调控的技术方法，成功实现了ZnO微腔激光的模式调控和单模输出。.4）利用合理的界面结构设计及缺陷调控改善了ZnO基电致发光器件的性能，进一步设计并制备了n-ZnO纳米棒/PEDOT/HfO2/p-GaN异质结器件，实现了电泵浦紫外纳米激光器。.5）以经典的磁控溅射技术制备了高质量ZnO核壳结构阵列，通过界面组分与能级配置的合理设计，探索了ZnO/ZnTe纯紫外-可见-红外超快响应、ZnO/AlN真空紫外响应及ZnO/Ga2O3超快日盲响应等不同核壳结构的光电探测器，解决了光催化剂面临的光生电荷快速复合、光利用效率低下和光腐蚀等问题。