Effect of carrier gas on the surface morphology of V-doped GaN layers

Vanadium-doped GaN (GaN:V) have been elaborated by metalorganic chemical vapour deposition (MOCVD). We have used vanadium tetrachloride (VCl4) to intentionally incorporate vanadium (V) during the crystal growth of GaN. The films were grown on sapphire substrate with tow procedures. A series of layers were elaborated under nitrogen (N2) and another under hydrogen (H2). For the growth of GaN:V in hydrogen atmospheric, we have used the SiN treatment consisting of an exposure of sapphire substrate to a mixture of ammonia (NH3) and silane (SiH4). In-situ laser reflectometry analysis show that the surface morphology of layers depends on VCl4 flow rate and the growth conditions. The experiments show that the quality of the grown layers (as measured with X-ray diffractometer (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) increases under N2.