An investigation of GaN thin films on AlN on sapphire substrate by sol-gel spin coating method

Abstract

In this research, the gallium nitride (GaN) thin films were deposited on aluminium nitride on sapphire (AlN/Al2O3) substrate by sol-gel spin coating method. Simple ethanol-based precursor with the addition of diethanolamine solution was used. The structural and morphology properties of synthesized GaN thin films were characterized by using X-ray Diffraction, Field-Emission Scanning Electron Microscopy and Atomic Force Microscopy. While the elemental compositions and the lattice vibrational properties of the films were investigated by means of the Energy Dispersive X-ray spectroscopy and Raman spectroscopy. All the results revealed that the wurtzite structure GaN thin films with GaN(002) preferred orientation and smooth surface morphology were successfully grown on AlN/Al2O3 substrate by using inexpensive and simplified sol-gel spin coating technique. The sol-gel spin coated GaN thin film with lowest oxygen content was also achieved.FESEM images show that GaN thin films with uniform and packed grains were formed. Based on the obtained results, it can be concluded that wurtzite structure GaN thin films were successfully deposited on AlN/Al2O3 substrate.