The effect of substrate temperature on the formation of β-C3N4-like crystallites by an inductively coupled plasma sputtering method has been investigated. Transmission electron diffraction patterns reveal that the structure of the microcrystallites formed is close to the theoretically predicted structure of β-C3N4. By using 100W of radio-frequency (RF) power for the deposition, the N/C atomic ratio in the film decreases from 0.35 to 0.07 upon increasing the substrate temperature from 100°C to 500°C. However, the crystallinity of the grains improves upon increasing the substrate temperature from 100°C to 400°C and then deteriorates drastically at 500°C, probably due to a deficiency of nitrogen in the film. By using 500W of RF power to increase the degree of gas dissociation, the formation of β-C3N4 crystallites is enhanced upon increasing the substrate temperature from 400°C to 800°C, with the N/C atomic ratio in the film decreasing only slightly from 1.0 to 0.85. At 800°C, the film deposited consists of large sizes of crystallites, as evidenced from the highly spotty electron diffraction pattern, and contains a high percentage (90%) of sp3 C-N bonding (i.e., the bonding of C3N4 crystallites) as estimated from X-ray photoelectron spectroscopy. The results suggest that, at a high degree of gas dissociation, the high substrate temperature is favorable for the synthesis of β-C3N4 crystallites.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Materials Chemistry
- Electrical and Electronic Engineering