Intrinsic carrier multiplication in layered Bi2O2Se avalanche photodiodes with gain bandwidth product exceeding 1 GHz

Vinod K. Sangwan, Joohoon Kang, David Lam, J. Tyler Gish, Spencer A. Wells, Jan Luxa, James P. Male, G. Jeffrey Snyder, Zdeněk Sofer, Mark C. Hersam*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Emerging layered semiconductors present multiple advantages for optoelectronic technologies including high carrier mobilities, strong light-matter interactions, and tunable optical absorption and emission. Here, metal-semiconductor-metal avalanche photodiodes (APDs) are fabricated from Bi2O2Se crystals, which consist of electrostatically bound [Bi2O2]2+ and [Se]2− layers. The resulting APDs possess an intrinsic carrier multiplication factor up to 400 at 7 K with a responsivity gain exceeding 3,000 A/W and bandwidth of ~ 400 kHz at a visible wavelength of 515.6 nm, ultimately resulting in a gain bandwidth product exceeding 1 GHz. Due to exceptionally low dark currents, Bi2O2Se APDs also yield high detectivities up to 4.6 × 1014 Jones. A systematic analysis of the photocurrent temperature and bias dependence reveals that the carrier multiplication process in Bi2O2Se APDs is consistent with a reverse biased Schottky diode model with a barrier height of ~ 44 meV, in contrast to the charge trapping extrinsic gain mechanism that dominates most layered semiconductor phototransistors. In this manner, layered Bi2O2Se APDs provide a unique platform that can be exploited in a diverse range of high-performance photodetector applications. [Figure not available: see fulltext.]

Original languageEnglish (US)
Pages (from-to)1961-1966
Number of pages6
JournalNano Research
Issue number6
StatePublished - Jun 2021


  • Schottky diode
  • high-frequency
  • impact ionization
  • layered semiconductor
  • photodetector

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • General Materials Science


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