基于ZnO半导体纳米线膜的声表面波型紫外探测器

Highly sensitive ultraviolet detector with ZnO nanowires film prepared on LiNbO_3 surface acoustic wave' wavelet device

针对传统半导体光电探测器件结构的宽带隙半导体紫外探测器可测信号弱的问题,提出了一种基于ZnO纳米线膜的声表面波型紫外探测器。该探测器利用ZnO纳米线膜的强紫外光电响应特性和声表面波器件的灵敏的声电相互作用机制,将采用高纯锌粉的热蒸发氧化工艺制备的纤锌矿型ZnO纳米线制作在已有声表面波小波传感器上。利用光致发光谱研究发现,由于低维激子限域效应和表面效应,所制作ZnO纳米线敏感膜中的紫外光电效应优于外延ZnO半导体薄膜;同时,基于ZnO纳米线膜的声表面波式紫外探测器在紫外光辐照下该探测器的中心频率减小,损耗增大。实验研究表明该器件能够实现长波紫外光的高灵敏度探测。

ZnO nanowires power with high yields were successfully synthesized via thermally evaporation of zinc power. Due to the size confinement for exciton and surface effects, the ZnO nanowires had a strong ultraviolet（UV） emission around 385nm and a very weak green emission around 500nm by photoluminescence（PL） spectra at room temperature （RT）. Therefore, a highly sensitive UV detector based on the surface acoustic wave （SAW） filter with ZnO nanowires film as UV light sensitive material was proposed. The UV detector was realized by simple transplanting process for ZnO nanowires film on the surface of SAW wavelet device and the effect of UV radiation on the frequency response of the detector was measured. Due to the acoustic - electric interaction, a downshift in the center frequency and an up - shift insert loss under UV illumination were observed by the frequency response of the SAW detector. Obviously, the new UV detector is preferable to the conventional photo - conductive semiconductor detector because both the strong interaction between the SAW and surface charge carriers, and the strong optical - electrical effect in the ZnO nanowires film were very useful for enhancing its sensitivity.