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Summary: Submitted to Phys. Rev. B 4/1/07
Kinetic energy induced smoothening and delay of epitaxial breakdown in pulsed
laser deposition
Byungha Shin and Michael J. Aziz*
Harvard School of Engineering and Applied Sciences, Cambridge, MA 02138
(Version of 4/1/2007)
Abstract
We have isolated the effect of kinetic energy of depositing species during pulsed
laser deposition (PLD) on surface morphology evolution of Ge(001) homoepitaxy at low
temperature (100 °C). Using a dual molecular beam epitaxy (MBE)-PLD chamber, we
compare morphology evolution from three different growth methods under identical
experimental conditions except for the differing nature of the depositing flux: (a) PLD
with average kinetic energy 300 eV (PLD-KE); (b) PLD with suppressed kinetic energy
comparable to thermal evaporation energy (PLD-TH); and (c) MBE. The thicknesses at
which epitaxial breakdown occurs are ranked in the order PLD-KE > MBE > PLD-TH;
additionally, the surface is smoother in PLD-KE than in MBE. The surface roughness of
the films grown by PLD-TH cannot be compared due to the early epitaxial breakdown.
These results convincingly demonstrate that the enhancement of epitaxial growth the
reduction in roughness and the delay of epitaxial breakdown are due to the high kinetic
energy of depositing species in PLD.
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