Performance enhancement of MgZnO ultraviolet photodetectors using ultrathin Al2O3 inserted layer

Hsin Ying Lee, Wu Han Tsai, Yu Chang Lin, Ching Ting Lee

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6 Citations (Scopus)


In this study, the magnesium zinc oxide (MgZnO) films and ultrathin alumina (Al2O3) inserted layers were subsequently deposited on sapphire substrates using a plasma-enhanced atomic layer deposition system, and applied in metal-semiconductor-metal ultraviolet (UV) photodetectors (MSM-UPDs). The dark current of the MgZnO MSM-UPDs was decreased from 1 to 0.34 nA with an increase in Al2O3 layer thickness from 0 to 5 nm. The ultrathin Al2O3 inserted layer effectively passivated the dangling bonds on the MgZnO surface and blocked leakage current. At a bias voltage of 5 V, the maximum UV-visible rejection ratio of the MgZnO MSM-UPDs was 1.78 × 103 with 5-nm-thick Al2O3 inserted layer. Furthermore, the noise equivalent power and detectivity of MgZnO MSM-UPDs with 5-nm-thick Al2O3 inserted layer were improved from 1.26 × 10-14 W and 2.50 × 1013 cm Hz1/2W-1 to 0.93 × 10-14 W and 3.40 × 1013 cm Hz1/2W-1 in comparison with MgZnO MSM-UPDs without Al2O3 inserted layer. The high performances of MgZnO MSM-UPDs were achieved by using ultrathin Al2O3 inserted layer.

Original languageEnglish
Article number051207
JournalJournal of Vacuum Science and Technology B: Nanotechnology and Microelectronics
Issue number5
Publication statusPublished - 2016 Sep 1

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry

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