STRUCTURAL-PROPERTIES OF INN FILMS GROWN ON GAAS SUBSTRATES - OBSERVATION OF THE ZINCBLENDE POLYTYPE

We report the first observation of the zincblende polytype of the InN semiconductor. InN films were grown on vicinal (100) GaAs substrates b y plasma enhanced molecular beam epitaxy. Transmission electron micros copy showed the InN films to be highly defective with both zincblende and wurtzite domains being present. The zincblende domains were epitax ially oriented to the substrate. The wurtzite InN had its c axis norma l to the [111] zincblende planes which suggests stacking faults as the nucleation mechanism of the hexagonal phase. X-ray diffractometry mea sured a lattice constant a = 0.498 +/- 0.001 nm for the zincblende InN polytype and a = 0.36 + 0.01 nm and c = 0.574 +/- 0.001 nm for the wu rtzite polytype.