🚀 go-pugleaf

In article <+40m-xm@lynx.unm.edu> Swami srinivasan writes:
>	Here's my question - is there a way to find a suitable 
>substrate or growing conditions whereby GaN can be grown cubic? If
>there are any references, please do send me the information. BTW,
>the reason i ask is that i recall someone having said that it was
>possible. 

Cubic GaN has been grown on beta-SiC (1) and basal plane sapphire (2).
(1) M.J. Paisley, Z. Sitar, J.B. Posthill, and R.F. Davis, ``Growth of 
    Cubic Phase Gallium Nitride by Gas Source Molecular Beam Epitaxy'', 
    Journal of Vacuum Science and Technology A, vol. 7 (1989) 701.

(2) T.P. Humphreys, C.A. Sukow, R.J. Nemanich, J.B. Posthill, R.A. 
    Rudder, S.V. Hattangady, and R.J. Markunas, ``Microstructural and 
    Optical Characterization of GaN Films Grown by PECVD on (0001) 
    Sapphire Substrates'', Materials Research Society Symposium 
    Proceedings, vol. 162 (1990) 531.

There have been a couple of reviews of the wide-band-gap nitride field
recently, and I recommend: 
S. Strite and H. Morkoc, J. Vac. Sci. Technol. B, 10(4), July/Aug 1992, 
pp. 1237-1266.  That ought to get you started.

>Are there any better substrates than Sapphire, which is the most 
>common one? 

Depends on exactly what you want grow and what technologies that you 
have for cleaning the substrates and growing the films. Lattice matching
is only one of several important factors required for ``good''
heteroepitaxial film growth. In short, there is no simple answer to your
question.  We must resort to the ubiquitous phrase, ``further research 
is required''.  Hope that helps.
-- 
John Posthill  jbp@rti.rti.org