GaN growth on Si with rare-earth oxide distributed Bragg reflector structures

• The two types of distributed Bragg reflectors (DBR) based on rare-earth oxide/Si stacks were prepared on Si(111) substrate by molecular beam epitaxy (MBE).
• GaN were grown on Si with DBR interlayers by metalorganic chemical vapour deposition (MOCVD) technique.
• GaN growth kinetics were monitored by in situ reflectance measurements.
• Structural and surface properties were analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD) and transmission electron microscopy (TEM).
• GaN films have shown c-orientated wurtzite structure with smooth, terrace like surface.

In this study, we prepared two types of distributed Bragg reflector structures based on Gd2O3/Si and Er2O3/Si stacks on Si(111) substrates for the growth of GaN. After determining the stability of the structures, GaN was grown in a three-stage process according to the metal-organic chemical vapor deposition method. Each stage of the process was controlled mainly by the growth temperature and monitored based on in situ reflectance measurements. The samples with GaN were characterized by atomic force microscopy, X-ray diffraction, and transmission electron microscopy. These analyses demonstrated that the deposited crystalline GaN had a wurtzite structure with a smooth surface. GaN grown on a Gd2O3/Si distributed Bragg reflector had a better GaN crystalline structure than that grown on Er2O3/Si despite the lower thermal stability of the oxide.