Analysis of the carbon-related 'blue' luminescence in GaN

Journal Article · Fri Apr 01 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1856224· OSTI ID:20668278

Armitage, R; Yang, Q; Weber, E R ^[1]

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1. Department of Materials Science and Engineering, University of California, Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

The properties of a broad 2.86-eV photoluminescence band in carbon-doped GaN were studied as a function of C-doping level, temperature, and excitation density. For GaN:C grown by molecular-beam epitaxy (MBE) the 2.86-eV band is observed in Si codoped layers exhibiting high n-type conductivity as well as in semi-insulating material. The peak position of the 'blue' luminescence is constant with temperature in MBE GaN, but in semi-insulating GaN:C grown by metal-organic vapor-phase epitaxy it shifts from 3.0 to 2.86 eV with increasing temperature in the range of 12-150 K. The 2.86-eV band undergoes thermal quenching from 200 to 400 K with an activation energy of {approx}150 meV. The characteristics of the 2.86-eV band are consistent with deep donor-deep acceptor recombination originating from carbon defects, under the assumption that the concentrations of these defects are low compared to the total carbon concentration in heavily C-doped samples. For low excitation density (4 W/cm{sup 2}) the 2.86-eV band intensity decreases as a function of HeCd laser exposure time over a period of many minutes. However, no transient effects are observed for 20 W/cm{sup 2} excitation density. The transient behavior can be best explained using a model based on charge-trapping-induced Coulomb barriers which impede the diffusion of carriers to the 2.86-eV luminescence centers.

• OSTI ID: 20668278
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 7 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
CARBON
CHEMICAL VAPOR DEPOSITION
COULOMB FIELD
DOPED MATERIALS
EV RANGE 01-10
GALLIUM NITRIDES
LASERS
MEV RANGE 100-1000
MOLECULAR BEAM EPITAXY
PHOTOLUMINESCENCE
QUENCHING
RECOMBINATION
SEMICONDUCTOR MATERIALS
SILICON
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
VAPOR PHASE EPITAXY