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Effect of Ga to N flux ratio on the GaN surface morphologies grown by plasma-assisted molecular-beam epitaxy

We mainly studied the morphology of GaN structures which were grown by plasma-assisted molecular beam epitaxy. The only condition we changed is Ga/N Ratio. Based on observation of reflection high energy electron diffraction (RHEED) patterns, we found all samples belong to two-dimensional (2D) growth mode. Also, based on scanning electron microscope (SEM) analysis, we found when Ga/N Ratio is 0.13 and 0.18, the surface of sample will be smoothest. Furthermore, based on the roughness result derived from atomic force microscope (AFM), we got the same result.
Then we observed the surface of samples after etching, we found all samples belong to Ga-face. Also, we can detect the degree of the state of mismatch under X-ray diffraction analysis. We found when Ga/N Ratio is 0.13, we got the lowest screw dislocation density; and when Ga/N Ratio is 0.18, we got the lowest overall dislocation density. In conclusion, we are trying to find sample growing parameters which could generate both better morphology and better structure.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0726107-014858
Date26 July 2007
CreatorsChang, Yao-i
ContributorsIkai Lo, Ming-Kwei Lee, Jih-Chen Chiang
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0726107-014858
Rightswithheld, Copyright information available at source archive

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