基于准分子灯的复合颗粒反射膜研究与制备

Research and Preparation of Composite Particle Reflective Film Based on Excimer Lamp

摘要: 基于介质阻挡放电的172 nm准分子灯在深紫外光源领域具有核心应用价值，但其光子各向同性发射导致的严重紫外能量损耗极大限制了其工业效率。目前，传统金属反射膜在真空紫外波段存在强烈的本征吸收损耗，而多层介质干涉膜则因依赖高端真空设备面临制备成本高昂的瓶颈。在此，本研究提出了一种基于溶胶–凝胶法制备的低损耗深紫外复合颗粒反射膜，为解决上述光子逸散难题提供了经济且高效的路径。依据半导体能带理论与Tauc法则，我们精准筛选出禁带宽度远超7.21 eV的SiO₂与Al₂O₃颗粒作为极低损耗的散射介质。结合米氏(Mie)散射理论与时域有限差分仿真，研究确立了300 nm SiO₂与100 nm Al₂O₃的最佳光学匹配尺寸。我们发现，当溶液固含量为35%时，颗粒能够形成致密的微观紧密堆积网络，将孔隙率降至最优的0.64%；同时，按6:4质量比混合SiO₂与Al₂O₃，可通过物理特性的互补有效耗散界面残余热应力，将膜层脱落率抑制在5%以下的极低水平。实验验证表明，该光学膜层不仅将准分子灯的中心照度显著提升至73.22 mW/cm²，提升率最高20.75%，更实现了变异系数仅为1.49%的超高照度均匀性。该研究提出了一种低成本、可扩展的复合氧化物反射膜制备方案，为高功率、高均匀性深紫外光源的规模化制造提供了一种可行性方案。

Abstract: 172 nm excimer lamps based on dielectric barrier discharge are of core value in deep-ultraviolet light source applications, yet their industrial efficiency is severely limited by ultraviolet energy loss caused by isotropic photon emission. Currently, traditional metal reflective films suffer from strong intrinsic absorption in the vacuum ultraviolet region, while multilayer dielectric interference films are bottlenecked by high manufacturing costs due to their reliance on high-end vacuum equipment. Here, we present a low-loss deep-ultraviolet composite particle reflective film fabricated via a cost-effective sol-gel method, providing an efficient pathway to address this photon dissipation challenge. Guided by semiconductor band theory and the Tauc method, we precisely identified SiO₂ and Al₂O₃ as ultra-low-loss scattering media, given that their band gaps far exceed 7.21 eV. Integrating Mie scattering theory with finite-difference time-domain (FDTD) simulations, we established the optimal optical matching sizes of 300 nm for SiO₂ and 100 nm for Al₂O₃. We demonstrate that a solid content of 35% enables a dense microscopic particle packing network, minimizing the porosity to an optimal 0.64%. Furthermore, blending SiO₂ and Al₂O₃ at a 6:4 mass ratio effectively dissipates interfacial residual thermal stress through complementary physical properties, suppressing the film detachment rate to an exceptionally low level of under 5%. Experimental validation reveals that this optical coating not only significantly boosts the central illuminance of the excimer lamp to 73.22 mW/cm² (an enhancement of up to 20.75%), but also achieves an ultra-high illuminance uniformity with a coefficient of variation of merely 1.49%. This study proposes a low-cost and scalable preparation scheme for composite oxide reflective films, providing a feasible solution for the large-scale manufacturing of high-power and high-uniformity deep ultraviolet light sources.