Selective growth of boron nitride nanotubes by plasma-enhanced chemical vapor deposition at low substrate temperature

Hexagonal boron nitride nanotubes (BNNTs) were synthesized at a low substrate temperature of 800 °C on nickel (Ni) coated oxidized Si(111) wafers in a microwave plasma-enhanced chemical vapor deposition system (MPCVD) by decomposition and reaction of gas mixtures consisting of B(2)H(6)-NH(3)-H(2). The 1D BN nanostructures grew preferentially on Ni catalyst islands with a small thickness only. In situ mass spectroscopic analysis and optical emission spectroscopy were used to identify the gas reactions responsible for the BNNT formation. The morphology and structural properties of the deposits were analyzed by SEM, TEM, EDX, SAD and Raman spectroscopy. The growth mechanism of the BNNTs was identified.