Method for manufacturing an ultra small grain-size nanocrystalline diamond film having a SiV photoluminescence

1. A method for manufacturing an ultra small grain-size nanocrystalline diamond film having SiV photoluminescence, comprises:

(1) manufacturing, on a single crystal silicon substrate, a nanocrystalline diamond film having SiV photoluminescence by using a microwave plasma chemical vapor deposition method,

(2) performing oxygen plasma etching treatment on the nanocrystalline diamond film obtained in step (1) for 5-30 min in a mixed gas plasma with an oxygen-nitrogen gas volume ratio of 1:4-6 and at an atmospheric pressure of 0.5-6 torr and a microwave power of 600-1000 W, thereby obtaining the ultra small grain-size nanocrystalline diamond film having the SiV photoluminescence.

2. The method according to claim 1 , wherein in the ultra small grain-size nanocrystalline diamond film having SiV photoluminescence, the size of the nanocrystalline diamond grains is 2.5 to 5 nm, and the size distribution is uniform.

3. The method according to claim 1 , wherein the thickness of the nanocrystalline diamond film prepared in step (1) is 1-3 μm, and the grain size in the film is 6-10 nm.

4. The method according to claim 1 , wherein the operation method of the step (1) is:

(a) Pretreatment: first, the single crystal silicon substrate is ultrasonically vibrated in a mixture of Ti powder, diamond micron powder and acetone for 45 min, then it is put in fresh acetone and ultrasonically vibrated for 1 min; after drying, it is placed in fresh acetone again and ultrasonically vibrated for 1 min; after drying, the substrate for nanocrystalline diamond film growth is obtained,

(b) Depositing film: the single crystal silicon substrate pretreated in step (a) is placed into a microwave plasma chemical vapor deposition apparatus to deposit a nanocrystalline diamond film; the microwave plasma chemical vapor deposition method use a mixed gas with a methane-argon volume ratio of 1-2:49 as the reaction gas and react at 400-500° C. for 1 h; thereby obtain a nanocrystalline diamond film has a thickness of 1-3 μm and a grain size of 6-10 nm on the single crystal silicon substrate surface.

5. The method according to claim 4 , wherein in the mixture of Ti powder, diamond micron powder and acetone, the concentration of Ti powder is 0.001 to 0.005 g/mL, and the concentration of diamond micron powder is 0.001 to 0.005 g/mL.