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G. Koblmüller, R. Averbeck, H. Riechert, Y. Hyun, P. Pongratz:
"Strain relaxation dependent island nucleation rates during the Stranski-Krastanow growth of GaN on AlN by molecular beam epitaxy";
Applied Physics Letters, 93 (2008), 234105-1 - 234105-3.

This study reports on the correlation between strain relaxation and nucleation kinetics during the Stranski-Krastanow growth of GaN on (0001)AlN by plasma-assisted molecular beam epitaxy. Using reflection high-energy electron diffraction and real-time desorption mass spectrometry, the strain-related Ga adatom detachment and desorption rates were determined, giving information about the average GaN island nucleation rate. Two different regimes were found: one at low-temperature growth (690<TS<720 °C), where strain relaxation occurred slowly, yielding impeded island nucleation rates and small island sizes (diameter ~8-12 nm and height ~2.3-2.7 nm). In the other, i.e., high-temperature growth regime (TS>720 °C), islands showed an abrupt relaxation mode, accompanied by a fast nucleation rate toward island sizes twice as large.

http://dx.doi.org/10.1063/1.3046730

http://dx.doi.org/10.1063/1.3046730