Nitrogen-ion-irnplantation synthesis of wurtzite GaN in GaP

α-GaN phase (wurtzite) was synthesized in GaP(100) by 140-keV N⁺ ₂ ion implantation with a dose of 3.0 × 10¹⁷ cm^-2 at 400°C and subsequent furnace annealing at 950°C for 20 min or rapid thermal annealing at 1000°C for 15 s. The traces of α-GaN were recognized by glancing-angle x-ray diffraction, supporting by the observation of the planes belonging to the [0100]-zone axis in α-GaN by a selected-area electron diffraction analysis. The formation of microcrystalline GaN of <1000 Å in size was confirmed by using Auger electron spectroscopy and cross sectional transmission electron microscopy. A ₁ transverse optical phonon mode in α-GaN was observed at around 525 cm^-1, indicating a nearly orientation relationship with GaN〈1120〉//GaP〈100〉.