Improved structural quality of GaN nanowall network grown on pre-nitrided c-sapphire

In the present study, GaN nanowall network (NWN) structures are grown using rf-plasma assisted molecular beam epitaxy (PA-MBE) system under highly nitrogen rich conditions over nitrided and bare c-plane sapphire substrates. Nitridation is carried out prior to growth for two of the samples and its effect on the crystal quality of the resultant nanowall structure is studied and compared with the same structure grown on bare sapphire. It is found that nitriding the c-plane sapphire prior to growth results in an improvement of crystalline quality of the resulting nanowall as observed by the reduction in FWHM of (0002) XRC.