High responsivity A-plane GaN-based metal-semiconductor-metal photodetectors for polarization-sensitive applications


Navarro A., Rivera C., Pereiro J., Munoz E., Imer B., DenBaars S. P. , ...More

APPLIED PHYSICS LETTERS, vol.94, no.21, 2009 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 94 Issue: 21
  • Publication Date: 2009
  • Doi Number: 10.1063/1.3143230
  • Journal Name: APPLIED PHYSICS LETTERS
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Keywords: current density, electrical resistivity, energy gap, gallium compounds, III-V semiconductors, metal-semiconductor-metal structures, photodetectors, polarisation, sapphire, wide band gap semiconductors, ULTRAVIOLET DETECTORS

Abstract

The fabrication and characterization of metal-semiconductor-metal polarization-sensitive photodetectors based on A-plane GaN grown on R-plane sapphire substrates is reported. These photodetectors take advantage of the in-plane crystal anisotropy, which results in linear dichroism near the band gap energy. The high resistivity of the A-plane GaN material leads to extremely low dark currents. For an optimized finger spacing of 1 mu m, dark current density and responsivity at 30 V are 0.3 nA/mm(2) and 2 A/W, respectively. A maximum polarization sensitivity ratio of 1.8 was determined. In a differential configuration, the full width at half maximum of the polarization-sensitive region is 8.5 nm.