高性能ZnS为基的紫外线检测器的技术回顾

对波长短于400 nm的紫外线有高灵敏度的探测器,在一些要求很高的可见光及红外线背景下作紫外线探测的应用是非常重要的.它们能在工业设备、科学研究以及消费产品开发新应用,例如火焰监控、光刻技术、 紫外线天文学、各种各样的先进医学和生物学仪器以及多种用于个人的紫外线监控产品.最近,我们已成功开发2种Ⅱ-Ⅵ族紫外线探测器：它们分别是以ZnSSe及ZnMgS为基的检测器.它们已经在商品化阶段.投产的商品包括紫外手表、个人紫外线监测器、新概念玩具和应用于教育部门的紫外线指数仪表及紫外线透射测试仪.这份报告会对这些新型器件作出详细的技术回顾.讨论集中于最近的研究成果：(1)萧特基(schottky)金属的问题、(2)防反射镀薄层以及(3)噪音和灵敏度检测.我们已制备并探讨了Au/Ni和Au/Cr双层萧特基接触.研究结果显示这些器件的光响应曲线相对于用纯Au作萧特基接触的器件,具有较低的抗可见光能力.利用二次离子质谱(SIMS)分析技术,发现Ni和Cr在Ⅰ～Ⅵ族材料中有严重的扩散以及它们在蒸镀过程中较易氧化.而且,也发现Au/Cr接触有金属合金现象.提出了一个考虑到由金属扩散及合金产生缺陷态的模型.相信这些缺陷态通过光激发及隧穿机制,严重地影响了在可见光频谱的光响应.我们的原本器件已经拥有高达60％的外部量子效率,但仍然受限于由于反射而导致的损失.在这项报告中,将讨论利用单层和多层防反射镀薄层的最新成果,也会探讨器件系统的灵敏度.我们已测量了器件的嗓音频谱密度、响应时间、频宽、光响应、在反向偏压下的暗电流及零偏压下的电阻.高达1014cm Hz1/2W-1的灵敏度已经达到.这些结果显示我们研制的新型紫外线探测器也适合于多种高档的应用,例如火焰传感器和紫外线照像机.

Technical review of high performance ZnS-based UV detectors

Recently, we have succeeded in the development of two novel Ⅱ-Ⅵ systems for UV radiation detection.They are already in commercialization stage. In this report, a technical review on these novel devices were presented. We have fabricated and studied both Au/Ni and Au/Cr bilayer Schottky contacts in this work. The results of our studies show that the photoresponse curves of these devices suffer much lower visible rejection power as compared to devices with pure Au as Schottky contacts. With the help of the secondary ion mass spectroscopy technique, we have identified a serious diffusion of these metals into Ⅱ-Ⅵ materials, as well as their ease of oxidization during deposition. Furthermore, we also detected the metal alloying in the Au/Cr contact. A model was proposed in this work to take into account the defect states generated through metal diffusion and/or alloying. Our recent achievement using single layer and multilayer anti-reflection coatings to improve the external quantum efficiency was discussed. A noise and detectivity study on the device system was also presented. A detectivity as high as 7.1 × 10 14number of high-end applications.