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Minority carrier diffusion lengths and optical self‐absorption coefficient in undoped GaN
Author(s) -
Matoussi A.,
Boufaden T.,
Guermazi S.,
Eljani B.,
Mlik Y.,
Toureille A.
Publication year - 2003
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200301870
Subject(s) - electron beam induced current , materials science , schottky diode , optoelectronics , diffusion , attenuation coefficient , schottky barrier , diode , depletion region , absorption (acoustics) , charge carrier , analytical chemistry (journal) , silicon , semiconductor , chemistry , optics , physics , chromatography , composite material , thermodynamics
In this paper we report electron beam induced current (EBIC) measurements on Schottky diodes on undoped GaN samples grown by the metal organic vapor phase epitaxy method on porous silicon substrates. A 2D simulation model was applied to perform the theoretical EBIC profiles and to compare with the experimental one. A minority carrier diffusion length ( L ) for holes of 0.72 μm was measured in the space charge region, indicating constant diffusivity of 6.48 cm 2 /s and a lifetime coefficient of 0.8 ns. An increase of L is observed as the probe source is moved from the Schottky junction to the bulk material. This increase was related to the polarization effects that are preponderant in group III–nitride devices. Far from the depletion layer (greater than 0.91 μm) the measured current is produced by the reabsorbed recombination radiation process. This corresponds to an optical self‐absorption coefficient of a p = 0.112 μm −1 . The results show that the transport parameters depend on the growth technology. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)