ZnO nanowire UV photodetectors with high internal gain
ZnO nanowire UV photodetectors with high internal gain
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DOI：
10.1021/nl070111x
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发表时间：
2007-04-01
期刊：
影响因子：
10.8
通讯作者：
Wang, D.
中科院分区：
文献类型：
--
作者：
Soci, C.;Zhang, A.;Wang, D.
制备了ZnO纳米线（NW）可见光盲紫外光电探测器，其内部光电导增益高达G，近似于10（8）。这些器件中的光电导机制已经通过跨越宽时域（从10（-9）到10（2）s）的时间分辨测量来阐明，揭示了载流子弛豫动力学的快（τ类似于20 ns）和慢（τ类似于10 s）分量的共存。极高的光电导增益归因于在NW表面处存在与氧相关的空穴陷阱态，这防止了电荷载流子复合并延长了光载流子寿命，如由光电流对环境条件的敏感性所证明的。令人惊讶的是，这种机制似乎是有效的，即使在最短的时间尺度研究的t < 1 ns。尽管弛豫时间慢，但ZnO NW光电探测器的极高内部增益导致增益带宽积（GB）高于类似于10 GHz。NW光电探测器的高增益和低功耗保证了新一代光电晶体管的应用，如传感，成像和芯片内光学互连。
ZnO nanowire (NW) visible-blind UV photodetectors with internal photoconductive gain as high as G similar to 10(8) have been fabricated and characterized. The photoconduction mechanism in these devices has been elucidated by means of time-resolved measurements spanning a wide temporal domain, from 10(-9) to 10(2) s, revealing the coexistence of fast (tau similar to 20 ns) and slow (tau similar to 10 s) components of the carrier relaxation dynamics. The extremely high photoconductive gain is attributed to the presence of oxygen-related hole-trap states at the NW surface, which prevents charge-carrier recombination and prolongs the photocarrier lifetime, as evidenced by the sensitivity of the photocurrrent to ambient conditions. Surprisingly, this mechanism appears to be effective even at the shortest time scale investigated of t < 1 ns. Despite the slow relaxation time, the extremely high internal gain of ZnO NW photodetectors results in gain-bandwidth products (GB) higher than similar to 10 GHz. The high gain and low power consumption of NW photodetectors promise a new generation of phototransistors for applications such as sensing, imaging, and intrachip optical interconnects.