GaN-based nanostructured photodetectors

Jose Luis Pau, Can Bayram, Paul Giedraitis, Ryan P McClintock, Manijeh Razeghi

Research output: Contribution to journalConference articlepeer-review

Abstract

The use of nanostructures in semiconductor technology leads to the observation of new phenomena in device physics. Further quantum and non-quantum effects arise from the reduction of device dimension to a nanometric scale. In nanopillars, quantum confinement regime is only revealed when the lateral dimensions are lower than 50 nm. For larger mesoscopic systems, quantum effects are not observable but surface states play a key role and make the properties of nanostructured devices depart from those found in conventional devices. In this work, we present the fabrication of GaN nanostructured metal-semiconductor- metal (MSM) and p-i-n photodiodes (PIN PDs) by e-beam lithography, as well as the investigation of their photoelectrical properties at room temperature. The nanopillar height and diameter are about 520 nm and 200 nm, respectively. MSMs present dark currents densities of 0.4 A/cm 2 at ±100 V. A strong increase of the optical response with bias is observed, resulting in responsivities higher than 1 A/W. The relationship between this gain mechanism and surface states is discussed. PIN PDs yield peak responsivities (R peak) of 35 mA/W at -4 V and show an abnormal increase of the response (R peak>100 AA) under forward biases.

Original languageEnglish (US)
Article number722214
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume7222
DOIs
StatePublished - Mar 23 2009
EventQuantum Sensing and Nanophotonic Devices VI - San Jose, CA, United States
Duration: Jan 25 2009Jan 28 2009

Keywords

  • E-beam lithography
  • Gallium nitride
  • III-nitrides
  • Metal-semiconductor-metal
  • Nanopillars
  • Nanostructures
  • Photoconductive gain
  • Photodetectors
  • Photodiodes
  • Ultraviolet

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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