Aligned carbon nanotubes (CNTs) were synthesized by nebulized spray pyrolysis of solutions of organometallics in carbon precursor solvents. Four types of straight-chained alkanes including n-pentane, n-hexane, n-heptane and n-octane were used as precursor solvents for synthesis of aligned CNTs. The results from scanning electron microscopy, transmission electron microscopy and Raman spectroscopy show that the CNTs obtained from them have different diameters and degrees of graphitization. It is found that the n-heptane is the most suitable for the growth of aligned CNTs with high quality and yield. The thermodynamic properties of precursory carbon sources such as boiling point and formation enthalpy are considered to play a decisive role in the synthesis of CNTs. It will be very helpful for the controllable preparation of aligned CNTs at relatively low cost.