Raman and infrared spectroscopy of GaN nanocrystals grown by chloride-hydride vapor-phase epitaxy on oxidized silicon

Raman and infrared spectroscopy were applied to study nanocrystalline GaN films grown by chloride-hydride vapor-phase epitaxy on SiO2/Si(111) substrates at T=520°C. It was ascertained that GaN nanocrystals are formed on the oxidized silicon surface at a rate of 10−2 nm/s. It was shown that the peaks in the Raman spectra E2(high)=566 cm−1 and A1(LO)=730 cm−1 correspond to the elastically strained GaN wurtzite structure. It was detected that a peak related to E1(TO)=558 cm−1 arises in the infrared spectra, which shows that elastic stresses in the nanocrystals are insignificant.