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Electrical characteristics of a ‐plane low‐Mg‐doped p‐GaN Schottky contacts
Author(s) -
Naganawa Moe,
Aoki Toshichika,
Son JiSu,
Amano Hiroshi,
Shiojima Kenji
Publication year - 2015
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.201451581
Subject(s) - materials science , schottky barrier , sapphire , doping , condensed matter physics , plane (geometry) , schottky diode , lamellar structure , optoelectronics , optics , composite material , geometry , physics , diode , laser , mathematics
Electrical characteristics of a variety of Schottky contacts formed with ten metal species on the a ‐plane of p‐type low‐Mg‐doped GaN grown on r ‐plane sapphire substrates were studied. We found that while current–voltage characteristics obtained under voltage scanning show no memory effect in samples formed on a ‐plane samples on c ‐plane showed a substantial memory effects. We consider that the absence of memory effect in the a ‐plane p‐GaN samples is originating from a smaller density of interfacial defect than that in the c ‐plane p‐GaN samples. In internal photoemission spectra, we observed two linearly increasing portions suggesting two different Schottky barriers with different heights coexisting in a contact. A potential barrier corresponding to a linear increase locating at lower photon energy typically ranged between 1.6 and 2.5 eV; and that corresponding to another linear increase locating at higher energy ranged between 0.7 and 1.7. The barrier heights showed no relevance to metal work function. The a ‐plane GaN surface was found to reveal a lamellar structure with stripes along [0001] direction with a randomly oriented roughness. We thus speculate that contact barrier spatially varies according to the different crystal plane.

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