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Title: Optical beam induced current measurements based on two-photon absorption process in 4H-SiC bipolar diodes

Using a pulsed green laser with a wavelength of 532 nm, a duration pulse of ∼1 ns, and a mean power varying between 1 and 100 mW, induced photocurrents have been measured in 4H-SiC bipolar diodes. Considering the photon energy (2.33 eV) and the bandgap of 4H-SiC (3.2 eV), the generation of electron-hole pair by the conventional single photon absorption process should be negligible. The intensity of the measured photocurrents depends quadratically on the power beam intensity. This clearly shows that they are generated using two-photon absorption process. As in conventional OBIC (Optical Beam Induced Current), the measurements give an image of the electric field distribution in the structure under test, and the minority carrier lifetime can be extracted from the decrease of the photocurrent at the edge of the structure. The extracted minority carrier lifetime of 210 ns is consistent with results obtained in case of single photon absorption.
Authors:
; ; ; ;  [1] ;  [2]
  1. Ampère Laboratory - UMR 5005, 21, Avenue Jean Capelle, 69621 Villeurbanne Cedex (France)
  2. Franco-Allemand Institute of Saint-Louis ISL, 5, Rue du Général Cassagnou, 68300 Saint-Louis (France)
Publication Date:
OSTI Identifier:
22293103
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION; CARRIER LIFETIME; ELECTRIC FIELDS; HYDROGEN 4; PHOTOCURRENTS; PHOTON BEAMS; PHOTONS; SILICON CARBIDES; WAVELENGTHS