Self-assembly In2Se3/SnSe2 heterostructure array with suppressed dark current and enhanced photosensitivity for weak signal

自组装制备In2Se3/SnSe2异质结构阵列来抑制暗电流和增强对弱信号的响应

Functional van der Waals(vdWs)heterostructures based on layered materials have shown tremendous potential in next-generation optoelectronic devices.To date,numerous vdWs heterostructures have been investigated based on stacking or epitaxial growth technology.However the complicated synthesis process greatly limits the large-scale integration of the heterostructure device array,which is essential for practical applications.Here,a planar photodetector array with an out-of-plane vertical In2Se3/SnSe2heterostructure as the photosensitive channel was self-assembled through a pulsed laser deposition(PLD)technique.The vertical built-in field was exploited to suppress the dark current and separate the photogenerated carriers.The realized devices possess an ultralow dark current of 6.3 p A,combined with a high detectivity of 8.8×1011Jones and a high signal-to-noise ratio(SNR)beyond 3×104.These performance metrics not only are one order of magnitude superior to pure In2Se3device,but also demonstrate the unique advantage of detecting weak signals.In addition,this heterostructure photodetector array can further be constructed on flexible polyimide(PI)substrate.These flexible devices also demonstrate effective light detection capability and the photoresponse remains unchanged even after 200 cycles of bending.These findings pave a way toward the development of next-generation large area and high integration optoelectronic technologies.

基于层状材料的范德华(vdWs)异质结构在下一代光电器件中显示出巨大潜力.迄今为止,基于堆叠或外延生长技术,已有多种vdWs异质结构被研究.然而,由于vdWs异质结的合成过程复杂,难以大规模集成异质结构器件阵列,对其实际应用造成了极大的限制.本文中,我们通过脉冲激光沉积技术自组装制备了面外垂直In2Se3/SnSe2异质结构的平面光电探测器阵列,利用垂直内建电场来抑制暗电流并分离光生载流子.所构建的器件具有6.3 pA的超低暗电流,8.8×1011Jones的高检测率和超过3×104的高信噪比.这些性能指标不仅比纯In2Se3器件高一个数量级,还展示了探测微弱信号的独特优势.另外,该异质结构光电探测器阵列也可以构建在柔性聚酰亚胺衬底上,制备柔性器件.这些器件同样显示出有效的光电探测能力,即使弯曲200次后,光响应仍保持不变.这些发现为下一代大面积和高集成度光电技术的发展奠定了基础.