氧化铝增强的PdSe_(2)/Si异质结光电探测器

Enhanced PdSe_(2)/Si heterojunction photodetector by Al2O3 layer

为了降低暗电流,通过原子层沉积(ALD)生长了一层氧化铝(Al_(2)O_(3))隧穿层,制备了PdSe_(2)/Al_(2)O_(3)/Si异质结光电探测器.通过优化Al_(2)O_(3)层的厚度,使得该探测器实现了高速和宽光谱响应.研究结果表明,在波长为808 nm的光照射和-2 V偏压下,所制备的光电探测器与未生长Al_(2)O_(3)的器件相比,暗电流降低了约3个数量级,器件的光响应度达到了约为0.31 A/W,对应的比探测率约为2.5×10^(12)Jones,器件在零偏压下表现出明显的自驱动效应.经过循环测试1 200次后,器件保持良好的光响应.器件响应的上升时间和下降时间分别为7.1和15.6μs.结果表明,在二维层状半导体材料与Si之间引入Al_(2)O_(3)隧穿层,可以有效地降低器件的暗电流,有利于高性能的Si基光电探测器的制备.

PdSe_(2)/Al_(2)O_(3)/Si heterojunction device was fabricated by inserting Al_(2)O_(3)tunneling layer grown by atomic layer deposition(ALD) in order to decrease the dark current. A fast and broadband photodetector was realized by optimizing the thickness of Al_(2)O_(3). Results showed that the dark current of PdSe_(2)/Al_(2)O_(3)/Si device was reduced by about 3 orders of magnitude compared with the device without Al_(2)O_(3)layer under 808 nm illumination and-2 V bias voltage. The photoresponsivity of the device was about 0.31 A/W and the corresponding specific detectivity was about 2.5×10^(12)Jones. The device exhibited obvious self-driving effect without bias. The device still maintained a better photoresponse after 1 200 cycles of cyclic testing. The rise time and fall time of photoresponse were 7.1 μs and 15.6 μs, respectively. The introduction of Al_(2)O_(3)tunneling layer between the two-dimensional layered semiconductor material and silicon can effectively reduce the dark current of the device and is beneficial to achieving high-performance silicon-based photodetectors.