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

Abstract

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.

Keywords

Be films / thermal evaporation / source to substrate distance / film growth / properties

References

[1] Haan SW, Salmonson JD, Clark DS, et al. NIF Ignition Target Requirements, Margins, and Uncertainties: Status February 2010[J]. Fusion Sci. Technol., 2011, 59(1): 1-7.

[2] Xu HW, Alford CS, Cooley JC, et al. Beryllium Capsule Coating Development for NIF Targets[J]. Fusion Sci. Technol., 2007, 51(4): 547-552.

[3] Temmerman G D, Baldwin MJ, Doerner RP, et al. Beryllium Deposition on International Thermonuclear Experimental Reactor First Mirrors: Layer Morphology and Influence on Mirror Reflectivity[J]. J. Appl. Phys., 2007, 102(8): 083 302

[4] Khomutov A, Barabash V, Chakin V, et al. Beryllium for Fusion Application- Recent Results[J]. J. Nucl. Mater., 2002, 307-311(12): 630-637.

[5] JOS Jr. Large-area Beryllium Metal Foils[J]. Nucl. Instr. and Meth. A, 1997, 397(1): 68-74.

[6] Jankowski AF, Wall M V, Buuren AW, et al. From Nanocrystalline to Amorphous Structure in Beryllium-based Coatings[J]. Acta Metall., 2002, 50(1): 4 791-4 800.

[7] Detor AJ, Hodge AM, Chason E, et al. Stress and Microstructure Evolution in Thick Sputtered Films[J]. Acta Metall., 2009, 57(1): 2 055-2 065.

[8] Xu HW, Alford C, Chason E, et al. Thick Beryllium Coatings by Ion-assisted Magnetron Sputtering[J]. J. Mater. Res., 2012, 27(5): 822-828.

[9] Luo BC, Li K, Tan XL, et al. Influences of In situ Annealing on Microstructure, Residual Stress and Eectrical Resistivity for Sputter-deposited Be Coating[J]. J. Alloys Compd., 2014, 607(1): 150-156.

[10] Pakarinen J, Polojärvi V, Aho A, et al. Annealing of Self-assembled InAs/GaAs Quantum Dots: A Stabilizing Effect of Beryllium Doping[J]. Appl. Phys. Lett., 2009, 94(7): 072 105

[11] Han MS, Kim JH, Jeong TS, et al. Growth and Optical Properties of Epitaxial BexZn1-xO Alloy Films[J]. J. Crystal Growth, 2007, 303(2): 506-509.

[12] Chowdhury MP, Roy RK, Chakraborty BR, et al. Beryllium-doped Polycrystalline GaN films: Optical and Grain Boundary Properties[J]. Thin Solid Films, 2005, 491(1-2): 29-37.

[13] Sun ZZ, Yoon SF, Loke WK. Electrical Properties of Silicon- and Beryllium- doped GaInP and (AlGa)InP Grown by Solid Source Molecular Beam Epitaxy[J]. J. Crystal Growth, 2002, 235(1-4): 8-14.

[14] Li K, Luo BC, Tan XL, et al. Temperature Effect on Properties of Be Films Grown by Thermal Evaporation[J]. J. Nucl. Mater., 2014, 449(1-3): 88-92.

[15] Li K, Luo BC, Zhang JQ, et al. Influence of Substrate Temperature on the Growth and Electrical Properties of Thermally Evaporated Be Films[J]. Fusion Eng. Des., 2015, 100(1): 307-313.

[16] Devika M, Reddy NK, Reddy DS, et al. Optimization of the Distance Between Source and Substrate for Device-grade SnS Films Grown by the Thermal Evaporation Technique[J]. J. Phys.: Condens. Matter., 2007, 19(30): 306 003

[17] Hagizawa T, Honma T, Kuroki Y, et al. Effects of Distance Between Tungsten Wire and Glass Substrate on Particle Size and Photochromic Characteristic of Tungsten Oxide Prepared by Electric Current Heating Method[J]. IOP Conf. Series: Mater. Sci. Eng., 2011, 18(9): 092 009

[18] Heng C. Infrared Physics[M]. 1985 Beijng: National Defence Industry Press. 301

[19] Feng W, Dong WW, Jun L, et al. Extraordinary Self-lubrication Properties of Non-hydrogenated Diamond-like Carbon Films Under Humid Atmosphere[J]. Sci. China. Ser. E-Tech. Sci., 2009, 52(4): 850-856.

[20] Gang FE, Ming ZD, Gong Z. Infrared Properties and Mechanism of Al-doped ZnO Thin Films[J]. Acta Metall. Sin., 2005, 41(3): 333-336.

[21] Lu JG, Bie X, Wang YP, et al. Transparent Conductive and Near-infrared Reflective Ga-doped ZnO/Cu Bilayer Films Grown at Room Temperature[J]. J. Vac. Sci. Technol. A, 2011, 29(3): 03A115