Formation of spherical Sn particles by reducing SnO2 film in floating wire-assisted H2/Ar plasma at atmospheric pressure
Thi‐Thuy‐Nga Nguyen, Minoru Sasaki, Takayoshi Tsutsumi, Kenji Ishikawa, Masaru Hori
Abstract
Abstract A green method to synthesize spherical Sn particles by reducing SnO 2 film in atmospheric-pressure H 2 /Ar plasma at low temperatures for various applications is presented. The floating wire-assisted remotely-generated plasma with a mixture of 0.05% H 2 /Ar gas formed spherical metallic Sn particles by reducing a SnO 2 layer on glass substrate. During the reduction process, H radical density was measured by using vacuum ultraviolet absorption spectroscopy, and plasma properties including electron density and gas temperature were diagnosed by optical emission spectroscopy. The inductively coupled generated plasma with a high electron density of 10 14 cm −3 , a hydrogen atom density of 10 14 cm −3 , and a gas temperature of 940 K was obtained at a remote region distance of 150 mm where the SnO 2 /glass substrate was placed for plasma treatment. The process has been modeled on the spherical Sn formation based on the reduction of SnO 2 films using H radicals. Depending on the treatment condition, the total reduction area, where spherical Sn particles formed, was enlarged and could reach 300 mm 2 after 2 min. The substrate temperature affected the expansion rate of the total reduction area and the growth of the Sn spheres.