Depleted Graphene-Oxide-Semiconductor Junctions for Photo-generated Electron and Hole Detection

Isaac Ruiz1, Michael D. Goldflam1, Joshua Shank1, Thomas E. Beechem1, Stephen W. Howell2

  1. Sandia National Laboratories
  2. Naval Surface Warefare Center, Crane

Analogous to the Metal-Oxide-Semiconductor (MOS) junction, the graphene-oxide-semiconductor (GOS) junction has been shown to be an effective way of detecting photo-generated charge within a depleted semiconductor, due to graphene’s sensitivity to nearby charge. Reducing the interface defect density at the semiconductor/oxide interface is one of the key challenges in reducing the dark charge current generation and increasing the responsivity and signal-to-noise ratio (SNR) of the detector. Here, we present a reduction of interface defect density in a silicon based deeply depleted graphene-oxide-semiconductor (D2GOS) junction for visible light detection, by passivating the silicon surface defects with a thermally grown oxide before depositing our gate dielectric by atomic layer deposition. A drastic reduction in dark charge generation at room temperature and almost complete elimination at liquid nitrogen temperatures was demonstrated using this method. With these fabrication improvements and the more thorough understanding of the doping effects on the D2GOS junction characteristics, we are able to understand the potential and limitations of this graphene-based detector.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.