Hopping conductivity and dielectric relaxation in Schottky barriers on GaN

A study of the current and capacitance dependences on the forward voltage in Au/n-GaN Schottky diodes, the sub-band optical absorption spectra, and the defect photoluminescence in n -GaN bulk crystals and thin layers is reported. It is shown that defect-assisted tunneling is the dominant transport m...

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Bibliographic Details
Published in:Semiconductors (Woodbury, N.Y.) N.Y.), 2017-09, Vol.51 (9), p.1186-1193
Main Authors: Bochkareva, N. I., Voronenkov, V. V., Gorbunov, R. I., Virko, M. V., Kogotkov, V. S., Leonidov, A. A., Vorontsov-Velyaminov, P. N., Sheremet, I. A., Shreter, Yu. G.
Format: Article
Language:English
Subjects:
ABSORPTION SPECTRA
Capacitance
Conduction bands
CRYSTAL DEFECTS
DIELECTRIC MATERIALS
Dielectric relaxation
Electric charge
Electric contacts
ELECTRIC FIELDS
Electric power distribution
Electric properties
ENERGY SPECTRA
GALLIUM NITRIDES
Hopping conduction
LABELLING
Liquor
Magnetic Materials
Magnetism
MASS SPECTROSCOPY
MATERIALS SCIENCE
MEV RANGE
NUCLEAR MAGNETIC RESONANCE
Photoluminescence
Physics
Physics and Astronomy
Physics of Semiconductor Devices
RELAXATION
SCHOTTKY BARRIER DIODES
Schottky diodes
SPACE CHARGE
THIN FILMS
TUNNEL EFFECT
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Summary:A study of the current and capacitance dependences on the forward voltage in Au/n-GaN Schottky diodes, the sub-band optical absorption spectra, and the defect photoluminescence in n -GaN bulk crystals and thin layers is reported. It is shown that defect-assisted tunneling is the dominant transport mechanism for forward-biased Schottky contacts on n -GaN. The dependences of the current and capacitance on forward bias reflect the energy spectrum of defects in the band gap of n -GaN: the rise in the density of deep states responsible for yellow photoluminescence in GaN with increasing energy and the steep exponential tail of states with an Urbach energy of E U = 50 meV near the conduction-band edge. A decrease in the frequency of electron hops near the Au/ n -GaN interface results in a wide distribution of local dielectric relaxation times and in a dramatic transformation of the electric-field distribution in the space-charge region under forward biases.
ISSN:1063-7826
1090-6479
DOI:10.1134/S1063782617090068