Influence of the Source to Substrate Distance on the Growth,Tribological Properties and Optical Properties of Be Films

The Be films were prepared by thermal evaporation at different sources to substrate distances (SSD) on glass substrates. The decrease of SSD from 90 mm to 50 mm caused the increase of substrate temperature and the rising density of incident Be atoms, thus the properties of Be films greatly changed accordingly. The experimental results showed that the grain diameter in the Be films transited from below 100 nm to 300 nm, the film growth rate increased from 2.35 nm/min to 4.73 nm/min and the roughness increased from 7 nm to 49 nm. The performance study suggested that the friction coefficient of Be films increased from 0.13 to 0.27 and was related to the surface roughness and inner structure, the near-infrared reflectance of Be films increased from 40% to 85% with the increase of wavelength and concurrently decreased with the decrease of SSD, respectively. The performance study indicated that the Be film had the potential application in specific near-infrared reflectance optical system.