Using AIN ceramic as substrate

we grow a series of diamond films under different CH

4

to H

2

volume ratio. Comparing their temperature-dependent PL from room temperature down to 100K and correlating the PL spectra with their Raman shift

we can get some of the structure and growth information. The intensity of diamond’s photoluminescence increases with the ratio of CH

4

to H

2

at first

and reaches its maximum when the CH

4

ratio is 3%. Afert that

PL decrease when the CH

4

growth rate continue to increase. We think the PL intensity might be caused by the recombination of defect states(such as stack fault). When the CH

4

concentration increase

the graphite components also increase

which enhance the possibility of non-radiative transition.