I. Grzegory, M. Bockowski, B. Lucznik, S. Krukowski, M. Wroblewski, S. Porowski
High Pressure Research Center
We present recent results on bulk GaN crystallization. The best quality GaN
crystals grown from the solution at high N2 pressure without an
intentional seeding are single crystalline platelets of stable morphology
reaching dimensions up to 10 mm. The fastest growth direction for such crystals
is [1 0 0], perpendicular to the GaN c-axis. The maximum stable
growth rate perpendicular to crystal c-axis is determined from the experiment
and used for an estimate of the effective supersaturation for the
{10
0} face assuming two dimensional layer growth. The heat of GaN
disssolution, determined from experimental solubility data, is used for the
estimation of the edge energy of 2-D nuclei on the growing {10
0}
face.
Bulk crystal growth seeded by a single hexagonal needle with well developed
{10
0} faces is also reported. The crystallization mechanisms and
morphological stability in seeded growth of GaN are discussed on the basis of
experimental results.
The physical properties of the GaN crystals and homoepitaxial layers grown on
them are briefly reviewed.