Cvd synthesis and the structure of vertically aligned cnt arrays

The structure and morphology of vertically aligned CNT (VACNT) arrays grown by CVD on Fe–Al 2 O 3 /Si(001) substrates are studied using scanning and high-resolution transmission electron microscopy (HRTEM) methods and Raman scattering. It is established that reproducible growth of continuous VACNT arrays is achieved only if the deposited Fe layer is at least 2 nm thick, while the particle size of the catalyst formed by annealing at 700 °C varies in a range of 2-10 nm and the array consists mainly of single- and double-walled CNTs with a diameter of 1-6 nm. The Raman spectrum is characterized by the presence of a radial breathing mode in the region 95-232 cm –1 and an intense G mode that is split into peaks at 1594 cm –1 and 1568 cm –1 upon laser excitation at the wavelength λ = 785 nm. According to the literature data, both modes indicate predominantly semiconductor nature of tubes in the array. The measured surface resistance of the VACNT array is 320±20 Ω/□.