A Raman spectroscopy study of the effect of thermal treatment on structural and photoluminescence properties of CVD diamond films

Abstract Micro- Raman spectroscopic technique is employed to investigate structural and micro-photoluminescence (μ-PL) properties of diamond films obtained by chemical vapour deposition (CVD) on silicon substrate. Information on the behaviour of PL centred at 2 eV upon annealing to 300 °C and cooling is obtained from background slope and G band intensity in the Raman spectra (the so-called S parameter). The results show that PL is thermally quenched and this process has a character of continuous of energy distribution due to point defects for temperatures below 100 °C. Additionally, the distribution of hydrogen concentration at the diamond films surface of different structures is estimated for room temperature and compared with the results obtained from atomic force microscopy (AFM). The obtained data indicate a correlation between the size and character of the grain boundaries and the hydrogen concentration.