The new oxide paradigm for solid state ultraviolet photodetectors

D. J. Rogers*, P. Bove, X. Arrateig, V. E. Sandana, F. H. Teherani, M. Razeghi, R. McClintock, E. Frisch, S. Harel

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

The bandgap of wurzite ZnO layers grown on 2 inch diameter c-Al2O3 substrates by pulsed laser deposition was engineered from 3.7 to 4.8 eV by alloying with Mg. Above this Mg content the layers transformed from single phase hcp to mixed hcp/fcc phase before becoming single phase fcc above a bandgap of about 5.5 eV. Metal-Semiconductor-Metal (MSM) photodetectors based on gold Inter-Digitated-Transducer structures were fabricated from the single phase hcp layers by single step negative photolithography and then packaged in TO5 cans. The devices gave over 6 orders of magnitude of separation between dark and light signal with solar rejection ratios (I270: I350) of over 3 × 105 and dark signals of 300 pA (at a bias of -5V). Spectral responsivities were engineered to fit the "Deutscher Verein des Gas- und Wasserfaches" industry standard form and gave over two decade higher responsivities (14 A/W, peaked at 270 nm) than commercial SiC based devices. Homogeneous Ga2O3 layers were also grown on 2 inch diameter c-Al2O3 substrates by PLD. Optical transmission spectra were coherent with a bandgap that increased from 4.9 to 5.4 eV when film thickness was decreased from 825 to 145 nm. X-ray diffraction revealed that the films were of the β-Ga2O3 (monoclinic) polytype with strong (-201) orientation. β-Ga2O3 MSM photodetectors gave over 4 orders of magnitude of separation between dark and light signal (at -5V bias) with dark currents of 250 pA and spectral responsivities of up to 40 A/W (at -0.75V bias). It was found that the spectral responsivity peak position could be decreased from 250 to 230 nm by reducing film thickness from 825 to 145 nm. This shift in peak responsivity wavelength with film thickness (a) was coherent with the apparent bandgap shift that was observed in transmission spectroscopy for the same layers and (b) conveniently provides a coverage of the spectral region in which MgZnO layers show fcc/hcp phase mixing.

Original languageEnglish (US)
Title of host publicationOxide-Based Materials and Devices IX
EditorsDavid J. Rogers, Ferechteh H. Teherani, David C. Look
PublisherSPIE
ISBN (Electronic)9781510615519
DOIs
StatePublished - Jan 1 2018
EventOxide-Based Materials and Devices IX 2018 - San Francisco, United States
Duration: Jan 28 2018Feb 1 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10533
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Other

OtherOxide-Based Materials and Devices IX 2018
CountryUnited States
CitySan Francisco
Period1/28/182/1/18

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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  • Cite this

    Rogers, D. J., Bove, P., Arrateig, X., Sandana, V. E., Teherani, F. H., Razeghi, M., McClintock, R., Frisch, E., & Harel, S. (2018). The new oxide paradigm for solid state ultraviolet photodetectors. In D. J. Rogers, F. H. Teherani, & D. C. Look (Eds.), Oxide-Based Materials and Devices IX [105331P] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 10533). SPIE. https://doi.org/10.1117/12.2319505