Polarity determination for MOCVD growth of GaN on Si(111) by convergent beam electron diffraction

摘要

The polarity of laterally epitaxially overgrown (LEO) GaN on Si(111) with an AlN buffer layer grown by MOCVD has been studied by convergent beam electron diffraction (CBED). The LEO GaN was studied by cross-section and plan-view transmission electron microscopy (TEM). The threading dislocation density is less than 10{sup}8 cm{sup}(-2) and no inversion domains were observed. CBED patterns were obtained at 200 kV for the〈1100〉zone. Simulation was done by many-beam solution with 33 zero-order beams. The comparison of experimental CBED patterns and simulated patterns indicates that the polarity of GaN on Si(111) is Ga face.