High-quality InN films on MgO (100) substrates: the key role of 30 degrees in-plane rotation
Compeán García, Vicente Damián
Orozco Hinostroza, Ignacio Everardo
Escobosa Echavarria, Arturo
López Luna, Edgar
Rodríguez Vázquez, Angel Gabriel
"High crystalline layers of InN were grown on MgO(100) substrates by gas source molecular beam epitaxy. Good quality films were obtained by means of an in-plane rotation process induced by the annealing of an InN buffer layer to minimize the misfit between InN and MgO. In situ reflection high-energy electron diffraction showed linear streaky patterns along the [01 (1) over bar0] azimuth and a superimposed diffraction along the [11 (2) over bar0] azimuth, which correspond to a 30 degrees alpha-InN film rotation. This rotation reduces the mismatch at the MgO/InN interface from 19.5% to less than 3.5%, increasing the structural quality, which was analyzed by high-resolution X-ray diffraction and Raman spectroscopy. Only the (0002) c plane diffraction of a-InN was observed and was centered at 2 theta = 31.4 degrees. Raman spectroscopy showed two modes corresponding to the hexagonal phase: E1(LO) at 591 cm(-1) and E2(high) at 488 cm(-1). Hall effect measurements showed a carrier density of 9 x 10(18) cm(-3) and an electron Hall mobility of 340 cm (2)/(V s) for a film thickness of 140 nm."