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Title: Improved efficiency of photoconductive THz emitters by increasing the effective contact length of electrodes

We study the effect of a surface modification at the interface between metallic electrodes and semiconducting substrate in Semi-Insulating GaAs (SI-GaAs) based photoconductive emitters (PCE) on the emission of Tera-Hertz (THz) radiation. We partially etch out a 500 nm thick layer of SI-GaAs in grating like pattern with various periods before the contact deposition. By depositing the electrodes on the patterned surface, the electrodes follow the contour of the grating period. This increases the effective contact length of the electrodes per unit area of the active regions on the PCE. The maxima of the electric field amplitude of the THz pulses emitted from the patterned surface are enhanced by up to more than a factor 2 as compared to an un-patterned surface. We attribute this increase to the increase of the effective contact length of the electrode due to surface patterning.
Authors:
; ; ;  [1] ;  [2]
  1. Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)
  2. Max Planck Institute for the Science of Light, Erlangen (Germany)
Publication Date:
OSTI Identifier:
22251277
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 3; Journal Issue: 12; Other Information: (c) 2013 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DEPOSITION; DEPOSITS; EFFICIENCY; ELECTRIC FIELDS; ELECTRODES; EMISSION; GALLIUM ARSENIDES; GRATINGS; INTERFACES; PULSES; SUBSTRATES; SURFACES