Low-voltage high-performance UV photodetectors: an interplay between grain boundaries and debye length

Renheng Bo, Noushin Nasiri, Hongjun Chen, Domenico Caputo, Lan Fu, Antonio Tricoli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


Accurate detection of UV light by wearable low-power devices has many important applications including environmental monitoring, space to space communication, and defense. Here, we report the structural engineering of ultraporous ZnO nanoparticle networks for fabrication of very low-voltage high-performance UV photodetectors. A record high photo-to dark-current ratio of 3.3 × 105 and detectivity of 3.2 × 1012 Jones at an ultralow operation bias of 2 mV and low UV-light intensity of 86 μW⋅cm-2 are achieved by controlling the interplay between grain boundaries and surface depletion depth of ZnO nanoscale semiconductors. An optimal window of structural properties is determined by varying the particle size of ultraporous nanoparticle networks from 10 to 42 nm. We find that small electron-depleted nanoparticles (≤40 nm) are necessary to minimize the dark-current; however, the rise in photocurrent is tampered with decreasing particle size due to the increasing density of grain boundaries. These findings reveal that nanoparticles with a size close to twice their Debye length are required for high photo-to dark-current ratio and detectivity, while further decreasing their size decreases the photodetector performance.

Original languageEnglish
Pages (from-to)2606-2615
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number3
Publication statusPublished - 25 Jan 2017
Externally publishedYes


  • visible-blind UV photodetectors
  • ultra-low voltage
  • nanoparticle networks
  • surface depletion
  • grain boundaries

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