Effects of phase separation and decomposition on the minority carrier diffusion length in AlxGa1-xN films



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Cremades Rodríguez, Ana Isabel and Albrecht, M. and Krinke, J. and Dimitrov, R. and Stutzmann, M. and Strunk, H. P. (2000) Effects of phase separation and decomposition on the minority carrier diffusion length in AlxGa1-xN films. Journal of Applied Physics , 87 (5). pp. 2357-2362. ISSN 0021-8979

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Official URL: http://jap.aip.org/japiau/v87/i5/p2357_s1


Combined electron beam induced current and transmission electron microscopy (TEM) measurements have been performed on both undoped and Si-doped AlGaN epitaxial films with aluminum contents x ranging from x = 0 to x = 0.79, in order to correlate the electrical and structural properties of the films. The diffusion length of holes in the films ranges between 0.3 and 15.9 mu m, and the estimated lifetime of holes for doped samples varies between 0.2 ns and 16 mu s. Different effects contribute to the observed increase in the diffusion length with increasing aluminum content. Among others, dislocations seem to be active as nonradiative recombination sites, and phase separation and decomposition as observed by TEM in Al-rich alloys lead to the formation of a spatially indirect recombination path due to the piezoelectric field in the films. Potential fluctuations associated with these phase irregularities could also give rise to electron induced persistent conductivity contributing to the increase of the diffusion length. From our experimental observations, we conclude that the silicon dopants are partially activated in Al-rich alloys, and do not influence significantly the values of the diffusion length of holes in these samples.

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© 2000 American Institute of Physics.
The authors thank Professor Piqueras for helpful discussions. A. Cremades thanks the Spanish Ministerio de Educación y Cultura for a postdoctoral grant. This work was supported by the Bayerische Forschungsstiftung (FOROPTO II).

Uncontrolled Keywords:N-Type Gan, Chemical-Vapor-Deposition, Persistent Photoconductivity, Yellow Luminescence, Quantum-Wells, Heterostructures, Relaxation, Lifetime, Centers
Subjects:Sciences > Physics > Materials
ID Code:23397
Deposited On:05 Nov 2013 19:04
Last Modified:07 Feb 2014 11:01

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