Influence of the growth temperature on the Si-V photoluminescence in diamond thin films

The influence of growth temperature (350 ÷ 1100 °C) on the intensity of Si-V colour centres photoluminescence was studied in diamond thin films. The films were grown by a microwave plasma enhanced chemical vapour deposition system. The film quality and surface morphology were characterised by Raman spectroscopy and scanning electron microscopy, respectively. For selected samples, the temperature behaviour of steady-state photoluminescence emission spectra was studied within the range 11 ÷ 300 K as well. The photoluminescence properties are related to the film growth temperature. We found that 800 °C is the optimal growth temperature, at which the highest intensity of the Si-V centre photoluminescence was observed. For all the samples, the blue shift in the position of the Si-V centre photoluminescence zero-phonon line is observed with decreasing temperature, which is attributed to the effects of lattice contraction and quadratic electron–phonon coupling. The zero-phonon line narrowing is discussed regarding vibrations of the perturbed lattice.