基于超宽β-Ga_(2)O_(3)微米带的日盲光电探测器研究

Solar blind photodetector based on ultra-wide β-Ga_(2)O_(3) microbelt

氧化镓的禁带宽度接近5 eV,是一种极具前景的日盲紫外探测半导体材料。基于碳热还原法生长高质量β-Ga_(2)O_(3)微米带制备出MSM(Metal-Semiconductor-Metal)结构光电导紫外探测器,研究了不同的结构对光电器件性能的影响。结果表明等间距叉指电极光电探测器相较于两端电阻型光电探测器有更优异的性能。在10 V/254 nm紫外光照下,其响应度、外部量子效率、比探测率和光响应时间等性能提高明显,其中光电流(Iphoto)有接近2个数量级的提升,且-2 V附近光暗电流比值增大至2.29×10^(5)。随着叉指电极间距从50μm缩减至20μm,器件Iphoto变大,其物理机制归因于阳极附近的耗尽层占据电极间微米带的比例增大引发了更高的光生载流子输运效率。

Gallium oxide with a band gap of nearly 5 eV is a promising semiconductor material for solar blind UV detection.Based on the high quality β-Ga_(2)O_(3) microbelts grown by the carbothermal reduction method,the photoconductive ultraviolet detectors with MSM(Metal-Semiconductor-Metal)structure were prepared.And the effects of different structures on the detectors were studied.The result shows that the detector with equidistance forked finger electrodes has better performance than that with two-end electrodes structure.Under 10 V/254 nm UV condition,the responsivity,external quantum efficiency,detectivity and photo-response time of the detector improve significantly.The photo current Iphoto has an improvement of nearly 2 orders of magnitude,and the light-dark current ratio at-2 V increases to 2.29×10^(5).It is also found that,Iphoto increases as the space of interdigital electrodes decreases from 50μm to 20μm.This can be ascribed to the higher transport efficiency of photo-generated carriers,which is induced by the increased proportion of the depletion layer near the anode occupying the microbelt between the electrodes.