Preparation Of Zirconium Films By Pulsed Laser Vapor Deposition And Its Properties

Zirconium is both an efficient, low-temperature equilibrium pressure common hydrogen storage materials, but also an indispensable nuclear structural material of high quality of nuclear research; even the applications in electrical, optical components have broad prospects. Although there have been some studies abroad on preparation and characterization of zirconium films。However, studies of zirconium films prepared by pulsed laser deposition method (PLD) are rarely reported. Zirconium deuteride film is no publicly reported in the literature. To take full advantage of zirconium core performance, hydrogen storage properties and the corresponding practical applications in electrical, optical aspects, the preparation and characterization of zirconium film must be scientific system solutions.In this paper, the main characterizations of zirconium films prepared by PLD deposition process are systematic investigated. The effects of pulsed laser frequency, pulse laser energy density and substrate temperature pulsed laser parameters such as the nature of the experimental conditions on the surface morphology of Zr film, deposition rate, phase structure, droplet distribution, electrical and optical, etc. Further study the effects of different substrates and pulsed laser frequency on the surface morphology, optical and electrical properties of deuterated zirconium films prepared by two-step methodBy varying the pulse parameters of the laser and the substrate temperature, zirconium film deposited on Si (100) by PLD were obtained, which are closely packed cubic phase a phase structure having the (110) crystal plane preferred growth direction. In smaller pulse laser frequency (2Hz), or pulsed laser energy density is low (2.1J/cm2), the zirconium film exhibited a surface amorphous form, its degree of crystallinity increased with the frequency or density enhance the energy density increases. Zirconia nanoparticle sizes in the film surface are substantially less than100nm (50-70nm). PLD deposited film during the deposition rate increases with the average frequency of the pulse laser light is reduced (2Hz when0.0056μg/pulse,20Hz when0.0012μg/pulse); deposition rate increases as the pulse energy density and sustained increase (2.1J/cm2when0.0025μg/pulse,10.6J/cm2when0.0038μg/pulse). The number and size of the droplets of zirconium film surface laser frequency increases with increasing pulse (2Hz when the average droplet size of1.5μm, number700,20Hz when the average droplet size4.5μm, Number4000); number of droplets with the increase of the size of the laser pulse energy density and sustained increase (2.1J/cm2average droplet size of0.7μm, number700,20Hz when the average droplet size4.2μm, number1600); reduced pulse laser frequency or pulsed laser energy density are conducive to obtaining the small number of droplets, small size and high surface smoothness zirconium film. It was found that, when the substrate temperature of450℃zirconium film and the silicon substrate combination reaction occurred, XRD first detected a new phase Zr2Si. The substrate temperature was350℃,450℃,550℃, zirconium deposited film thickness was obtained in220,160and120nm, but the rate of resistance were26,16,12μΩcm. The resistivity of the films decreases with increasing temperature, and then decrease with decreasing thickness, show special electrical properties.By using PLD, zirconium films deposited on Mo substrate were obtained by varying the frequency of the laser. These films are typical a hexagonal close-packed structures but did not show preferential growth of crystal planes. The average grain size of nanoparticle (80-125nm) is much higher than the average grain size of nanoparticle deposited on Si (100) substrateZirconium films deposited on Al2O3(0001) substrates at different frequencies are still the a-phase hexagonal structure. A relatively low frequency pulsed laser (2Hz,6Hz), zirconium film obtained at10Hz show the strongest intensity of each peak, the best crystallinity. The RMS values under such conditions are about1nm, far below the values deposited on Si (100) or Mo substrates. Zirconium films prepared on Al2O3(0001) substrates have a very smooth, flat surface and the RMS values is very low. Its specular reflectance at a wavelength of800n m is up to75%. With respect to the Si (100) substrate, zirconium films grown on Al2O3(0001) substrate have a higher specular reflectance.A two-step method was introduced to complete the process of deuteration for zirconium films.zirconium films deposited on Si (100) substrate were deuterated on the temperature350℃and show the phase of ZrD2,.zirconium films deposited on Al2O3(0001) substrate were deuterated on the temperature650℃and showed the phase of Zr0.38D0.62phase,. Compared to the smaller pulsed laser frequency (2Hz), zirconium film deposited at higher laser pulse frequency (8Hz) was formed on the surface with more holes tunnel after the process of deuteration. When the laser pulse frequency is10Hz, with respect to the film before the process of deuteration, its resistance value decreased by20%, specular reflectance decreased by30%, the change values reached a maximum. After the deuterated process, the surface obtained at higher pulsed laser frequency show a smoother surface, higher resistance and lower specular Reflectivity. A lot of nanoscale trenches and holes formed on the surface of Zr films after the deuterated process. The amount of deuterium droplets film surface is far greater than the amount absorbed by the absorption film itself. Because the deuterium atoms in the lattice expansion of zirconium occupied in tetrahedral gap becomes negligible, deuterium atoms react with droplets produced more deuterated zirconium.