Atomically thin lateral p-n junction photodetector with large effective detection area

Zai-Quan Xu, Yupeng Zhang, Ziyu Wang, Yuting Shen, Wenchao Huang, Xue Xia, Wenzhi Yu, Yunzhou Xue, Litao Sun, Changxi Zheng, Yuerui Lu, Lei Liao, Qiaoliang Bao

Research output: Contribution to journalLetterResearchpeer-review

49 Citations (Scopus)


The widely used photodetector design based on atomically thin transition metal dichalcogenides (TMDs) has a lateral metal-TMD-metal junction with a fairly small, line shape photoresponsive active area at the TMD-electrode interface. Here, we report a highly efficient photodetector with extremely large photoresponsive active area based on a lateral junction of monolayer-bilayer WSe2. Impressively, the separation of the electron-hole pairs (excitons) extends onto the whole 1L-2L WSe2 junction surface. The responsivity of the WSe2 junction photodetector is over 3200 times higher than that of a monolayer WSe2 device and leads to a highest external quantum efficiency of 256% due to the efficient carrier extraction. Unlike the TMDp-n junctions modulated by dual gates or localized doping, which require complex fabrication procedures, our study establishes a simple, controllable, and scalable method to improve the photodetection performance by maximizing the active area for current generation.

Original languageEnglish
Article number041001
Number of pages9
Issue number4
Publication statusPublished - 23 Sep 2016


  • Effective detective area
  • Lateral p-n junction
  • Optoelectronics
  • Photocurrent mapping
  • Transition metal dichalcogenides

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