通过氟修饰提高氧气吸附脱附性能以获得高性能ZnO纳米线基紫外探测器

Ultraviolet (UV) photodetectors have been widely used in various commercial and military applications. Nowadays, UV detectors based on wide bandgap semiconductors have received more and more attention due to their intrinsic visible-blindness. In particular, nanowire photodetectors have been the subject of extensive investigations during people having the desire for nanoscale photoelectric devices. ZnO nanowire has been studied extensively in recent years because it has strong radiation hardness, high chemical stability, low cost, and a large bandgap at room temperature. Nowadays, ZnO nanowires UV photodetectors have very high phototosensitivity. However, the performance of these photodetectors was not good enough and the response speed was still low. It was believed that, the performance of these photodetectors was sensitively dependent on nanowires surface structures and the adsorption and desorption process of oxygen. The response speed can be improved by avoiding oxygen adsorption, but the phototosensitivity will reduce drastically. It is hard to fabricate ZnO nanowires UV photodetector with high photosensitivity and high response speed. In this program, we promote ability of oxygen adsorption and desorption by surface-fluorination of ZnO nanowires, and prepare ZnO nanowires UV photodetectors with relative high photosensitivity and response speed.

紫外探测器在航天、军事、民用领域均有广泛的应用需求。目前，紫外探测器的研究热点主要集中于宽禁带半导体材料上，同时随着人们对纳米级光电器件的渴望，制备一维纳米结构的紫外探测器成为很有前景的研究方向。ZnO具有禁带宽度大，稳定性好，原料丰富易得，价格低廉，其一维纳米材料结构丰富，容易制备等优点，在紫外探测领域备受关注。目前ZnO纳米线基紫外探测器可以得到很高的光响应度，但是响应时间普遍较长。而这一现象主要是ZnO纳米线表面氧气吸附和脱附速率太慢所造成的。如果避免ZnO纳米线对氧气的吸附，则可以提升响应速度，但是光响应度会大幅度下降。ZnO纳米线基紫外探测器很难兼顾响应度和响应时间这两个重要参数。本项目通过表面选择性氟基团化，获得氧气吸附量高、氧气吸附脱附速率快的ZnO纳米线材料，并以此构建具有较高响应度和较快响应速度的ZnO纳米线基紫外探测器。

紫外探测器在航天、军事、民用领域均有广泛的应用需求。目前，紫外探测器的研究热点主要集中于宽禁带半导体材料上。ZnO具有禁带宽度大，稳定性好，原料丰富易得，价格低廉，其一维纳米材料结构丰富，容易制备等优点，在紫外探测领域备受关注。目前ZnO基紫外探测器可以得到很高的光响应度，但是响应时间普遍较长。而这一现象主要是ZnO基材料表面氧气吸附和脱附速率太慢所造成的。如果避免ZnO基材料对氧气的吸附，则可以缩短响应时间，但是光响应度会大幅度下降。ZnO基紫外探测器很难兼顾光响应度和响应时间这两个重要参数。.针对以上难题，本项目通过表面选择性氟基团化，获得氧气吸附量高、氧气吸附脱附速率快的ZnO基材料，并以此构建具有较高响应度和较短响应时间的ZnO基紫外探测器。其中氟基团的修饰使得表面氧气的吸附量增加，所以器件的响应度增加。另外，氟基团的修饰使得表面氧气的吸附速度变快，所以器件的响应时间变短。器件的响应度可以达到300A/W以上, 暗电流低至0.4pA，响应时间可以低至4微秒，紫外抑制比可以达到4个量级。.因此，该方法有助于解决传统器件中很难兼顾光响应度和响应时间这两个重要参数的问题，从而有望实现高性能的ZnO基紫外探测器。