Effect of NH3 flow rate on morphologic and optical properties of InN dots grown by flow-rate modulation epitaxy

• Main Authors: Chen, Ying-Chung, 陳膺中
• Other Authors: Chen, Wei-Kuo
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/65401544964054371219

碩士 === 國立交通大學 === 電子物理系所 === 100 === In this thesis, we proposed flow-rate modulation epitaxy （FME） to fabricate InN nanostructures. We use FME mode that an alternative supply of group-III and group-V sources to grow InN under 600℃, and growing under low background NH3 flows at 250 sccm during In step. Atomic force microscopy（AFM）, X-ray diffraction（XRD）and Photoluminescence（PL）measurements were used to investigate the morphology and optical properties of InN nanodots. Our experients show that In droplets were observed and the poor of optical qualities when NH3 flow rate below 1000 sccm at N-step. On the other III hand, stronger PL emission peaks at around 0.75 eV and linewidth about 75 meV is shown for NH3 flows higher than 1500 sccm. And FME growth mode is advantaged that no suppression of the growth efficiency even for V/III at 60000 is observed in comparison with published results using conventional mode that 75 % of growth rate is reduced once V/III larger than 30000. Together with the sustained photoluminescence efficiency, which peaks at 0.75 eV, this result reveals that FME suppresses the formation of stacking faults of nitrogen atoms under high V/III ratio regime.