Graphene/Al2O3/Si Schottky diode with integrated waveguide on a silicon-on-insulator wafer


Seven E., ORHAN E., Di Bartolomeo A., ERTUĞRUL M., Taştekin N. A.

Indian Journal of Physics, vol.98, no.8, pp.2795-2803, 2024 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 98 Issue: 8
  • Publication Date: 2024
  • Doi Number: 10.1007/s12648-023-03062-7
  • Journal Name: Indian Journal of Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, INSPEC, zbMATH
  • Page Numbers: pp.2795-2803
  • Keywords: Graphene, Ideality factor, Schottky barrier, Series resistance, Silicon-on-insulator (SOI), Waveguide
  • Karadeniz Technical University Affiliated: Yes

Abstract

Waveguide-integrated graphene photodiodes are on-chip optoelectronic devices with promising applications in telecommunications. Here, we present the electrical properties of a heterostructure consisting of multilayer graphene (MLGr) over a Si waveguide covered by an ultrathin Al2O3 layer. The waveguide is fabricated by etching a silicon-on-insulator (SOI) substrate with 220 nm Si and 1.5 μm buried oxide. The 5 nm-thick Al2O3 film is deposited by atomic layer deposition (ALD), while graphene, synthesized on copper by chemical vapor deposition (CVD), is transferred onto the Al2O3/Si rib by a wet transfer method. The MLGr/Al2O3/Si rib forms a Schottky structure with rectifying current–voltage characteristics, which are examined using the thermionic emission theory and Norde’s method. A Schottky barrier height Φ B= 0.79 eV , an ideality factor n = 26, and a series resistance R S= 11.6 M Ω are obtained. The device is promising for operation at the optical fiber communication wavelength of 1550 nm.