PHOTOSIGNAL ENHANCEMENT IN AL-GAAS DIODES DUE TO SURFACE-PLASMONS AND GUIDED-WAVE MODES

IR TAMM*, P DAWSON, MA PATE, R GREY, G HILL

*Corresponding author for this work

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Light of wavelength 632.8 nm and p-polarization is incident on a prism-air gap (varied from 0.7 to 7 mum)-Al-GaAs arrangement. Both the photosignal generated by the Schottky diode and the reflectance are measured as a function of the internal angle of incidence in the prism. There is significant, well-defined enhancement of the photosignal, up to a factor of approximately 7.5, associated with two different types of enhanced absorption modes. For air gaps <1.5 mum there is photosignal enhancement due to an enhanced absorption feature (reflectance dip) that occurs at an angle of incidence just above critical angle in the prism; this feature corresponds to the excitation of a surface plasmon polariton at the Al-air interface. For air gaps > 1 mum there are between one and ten photoresponse peaks at input angles less than the critical angle. The corresponding enhanced absorption features are due to leaky guided wave modes set up in the air gap.

Original languageEnglish
Pages (from-to)7481-7487
Number of pages7
JournalJournal of Applied Physics
Volume74
Issue number12
Publication statusPublished - 15 Dec 1993

Keywords

  • SEMICONDUCTOR JUNCTIONS
  • INTERNAL PHOTOEMISSION
  • QUANTUM EFFICIENCY
  • PHOTODETECTION
  • DETECTORS
  • METALS

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