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Impact of O 2 flow rate on the growth rate of ZnO(0001) and ZnO(000 1 ‾ ) on GaN by plasma‐assisted molecular beam epitaxy
Author(s) -
Adolph David,
Ive Tommy
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201552764
Subject(s) - volumetric flow rate , growth rate , molecular beam epitaxy , materials science , analytical chemistry (journal) , emission intensity , plasma , emission spectrum , intensity (physics) , full width at half maximum , epitaxy , photoluminescence , optoelectronics , layer (electronics) , chemistry , spectral line , nanotechnology , optics , chromatography , physics , geometry , mathematics , quantum mechanics , astronomy
We studied the effects of a varying O 2 flow rate on the growth of ZnO(0001) and ZnO(000 1 ‾ ) layers onGaN / Al 2 O 3 templates by plasma‐assisted molecular beam epitaxy. The O 2 flow rate through the O‐plasma source was varied between 0.25 and 4.5 standard cubic centimeters per minute (sccm) corresponding to a growth chamber pressure between 3.0 × 10 − 6and 5.0 × 10 − 5Torr. We found that the change of the O 2 flow rate had a profound effect on the ZnO layer growth rate. A maximum growth rate was reached for an O 2 flow rate of 1.0–2.0 sccm. The same growth rate dependence on the O 2 flow rate was observed for ZnO(0001) layers that were grown on GaN/4H‐SiC buffer layers for verification. To assess the amount of active O contributing to the ZnO‐growth, the spectral composition of the plasma was investigated with optical emission spectroscopy. The integrated optical emission line intensity reached a maximum for an O 2 flow rate between 1.0 and 2.0 sccm. Essentially all emission lines exhibited a maximum intensity for an O 2 flow rate between 1.0 and 2.0 sccm thus coinciding with the flow rate yielding the maximum growth rate.