Effects of NH3 Flow Rate on the Growth Mechanism and Optical Properties of InN Crystallites Fabricated by Chemical Vapor Deposition

摘要

Chemical vapor deposition (CVD), as a conventional and effective approach, has been widely used for the fabrication of InN materials. Typically, CVD processes are supposed to be dominated by different chemical and thermodynamical parameters. NH3 flow rate has been proved to be an important factor that could influence the morphology of InN nanostructures. However, it is rare to have a report on the effect of the NH3 flow rate on the growth mechanism of InN crystallites within CVD processes. In this work, it is manifest that the uniform InN nanowires are synthesized at the NH3 flow rate of 240 sccm. While the NH3 flow rate increases to 350 sccm, large numbers of InN microcrystallites with a pyramid shape are obtained instead. It is also found that a higher NH3 flow rate may trigger a self-assembly growth process in the CVD system, subsequently influencing the morphological characteristics and even the optical properties of the products. Thus, adjusting the NH3 flow rate may be an important approach to tailor the morphology and properties of Group III nitrides via CVD processes.