Phase Separation in wurtzite In1-x-yGaxAlyN
T. Matsuoka
Nippon Telegraph and Telephone Corp. (NTT)
This article was received on Monday, June 22, 1998 and
accepted on Friday, December 4, 1998. Abstract
The wurtzite structure In1-x-yGaxAlyN
quaternary system is studied with respect to the unstable region in mixing.
The composition in the unstable region is calculated from the free energy of
mixing by using the strictly regular solution model. The interaction parameter
used in this calculation is obtained by using the delta-lattice-parameter
method. Here, the proportionality constant connecting the lattice constants
and the band-gap energy is determined by fitting the calculation to the
composition data obtained experimentally from InGaN grown by metallorganic
vapor phase epitaxy. From this calculation, the ternary alloys of InAlN, InGaN
and GaAlN are predicted to always, sometimes, and hardly ever, respectively,
have an unstable mixing region. The essential mismatch in thermal equilibrium
between the strictly regular solution approximation and the growth conditions
in MOVPE is removed by using a fitting calculation and experimental data.
Also, the mismatch between the zinc-blende structure and the wurtzite structure
is corrected. As a result, this prediction of the phase separation in
In1-x-yGaxAlyN becomes more
reliable.Outline
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Cite this article as: MRS Internet J. Nitride Semicond. Res. 3, 54(1998).
last updated Friday, December 4, 1998 10:37:33 PM.© 1998 The Materials Research Society
