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Title: Effects of defect clustering on optical properties of GaN by single and molecular ion irradiation

The effects of irradiation by F, P, and PF{sub 4} on optical properties of GaN were studied experimentally and by atomistic simulations. Additionally, the effect of Ag was studied by simulation. The irradiation energy was 0.6‚ÄČkeV/amu for all projectiles. The measured photoluminescence (PL) decay time was found to be decreasing faster when irradiation was done by molecular ion compared to light ion irradiation. The PL decay time change is connected with the types of defect produced by different projectiles. Simulation results show that the light ions mainly produce isolated point defects while molecular and heavy ions produce clusters of point defects. The total amount of defects produced by the PF{sub 4} projectile was found to be very close to the sum of all defects produced in five individual cascades started by one P and four F single ions. This and the similar depth profiles of damage produced by molecular and light ion irradiations suggest that the defect clusters are one of the important reasons for fast PL decay. Moreover, the simulations of irradiation by Ag ions, whose mass is close to the mass of the PF{sub 4} molecule, showed that the produced defects are clustering in even bigger conglomerates comparedmore » to PF{sub 4} case. The latter has a tendency to split in the pre-surface region, reducing on average the density of the collision cascade.« less
Authors:
; ; ;  [1] ; ; ;  [2]
  1. Department of Physics, University of Helsinki, P.O. Box 64, FIN 00014 (Finland)
  2. Department of Physical Electronics, St. Petersburg State Polytechnic University, St. Petersburg (Russian Federation)
Publication Date:
OSTI Identifier:
22259298
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CONGLOMERATES; GALLIUM NITRIDES; HEAVY IONS; IRRADIATION; LIGHT IONS; MOLECULAR IONS; OPTICAL PROPERTIES; PHOTOLUMINESCENCE; POINT DEFECTS; SILVER IONS; SIMULATION