Two step growth of high quality long n-GaN:Si nanowires using μ-GaN seed on Si(111) by metalorganic chemical vapor deposition

•Long n-GaN:Si nanowires were grown on Si(111).•Metalorganic chemical vapor deposition with two-step process was used.•Initially, μ-GaN seeds were grown at low temperature by pulsed growth method.•The temperature was increased to grow the long nanowires by continuous flow mode.•The effect of μ-GaN seed on the growth rate was examined.

A two-step growth method for growing high quality long n-GaN:Si nanowires (NWs) on Si(111) substrates using metalorganic chemical vapor deposition (MOCVD) was developed. In the primary step μ-GaN seeds were grown at 710 °C by pulsed growth method using MOCVD and in the secondary stage, we suitably increased the growth temperature to 950 °C in order to grow the high quality long n-GaN:Si NWs by continuous flow mode. We grew n-GaN:Si NWs at various pairs of μ-GaN seed so as to examine its effect on the growth rate. The density and length of n-GaN:Si NWs were improved with the increase of seeds up to 10 pairs. The number of seed pairs determines the density and length of n-GaN:Si NWs, but they did not affect its diameter directly. Field emission scanning electron microscopy, X-ray diffraction, photoluminescence, cathodoluminescence and high-resolution transmission electron microscopy were used to characterize the specimens.