Growth and characterization of GaP nanowires on Si substrate.

The integration of III-V semiconductor materials with Si technology is of great interest for optoelectronic integration circuits. We have studied the growth and structural aspects of GaP nanowires (NWs) grown on Si substrate in a metalorganic vapor phase epitaxy system. Au colloid particles dispersed on Si substrate were used as catalysts to conduct the NW growth. The growth temperature considerably affected the growth rate and shape of GaP NWs. The growth rate showed a maximum value of 14.69 nm/s at 480 °C. When growth temperature increased the radial growth on NW sides was enhanced and the NWs therefore exhibited a tapering shape. GaP NWs with a uniform diameter could be grown at a growth temperature as low as 420 °C using a two-temperature process. The NW diameter could be well controlled by using size-selective Au colloid particles. The growth rate dependence showed that the thin NWs grew more slowly than thick ones and the V/III source ratio had a significant effect on the growth rate dependence. An analysis of the GaP/Si interface by transmission electron microscopy indicated that the NWs were epitaxially grown on the Si(111) substrate. Based on these experimental results, the growth mechanism of the GaP NWs on Si was discussed. [ABSTRACT FROM AUTHOR]