2017年第78回応用物理学会秋季学術講演会

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一般セッション(口頭講演)

9 応用物性 » 9.2 ナノワイヤ・ナノ粒子

[6p-S44-1~21] 9.2 ナノワイヤ・ナノ粒子

2017年9月6日(水) 13:15 〜 19:00 S44 (第5会議室)

深田 直樹(物材機構)、石川 史太郎(愛媛大)、清水 智弘(関西大)

18:00 〜 18:15

[6p-S44-18] Effect of Au thickness on the Bimetal-catalyzed Growth of InGaZnO Nanowires
from Amorphous Thin Film

〇(M1)JenichiClairvaux Escubio Felizco1、Mutsunori Uenuma1、Daiki Senaha1、Yasuaki Ishikawa1、Yukiharu Uraoka1 (1.NAIST)

キーワード:bi-metal, IGZO, nanowire

Although considerable research has been devoted to InGaZnO in amorphous phase, rather less attention has been given to its crystalline state, especially in nanostructured form. In particular, a few literatures have reported the fabrication of InGaZnO nanowires. Moreover, these studies employed extremely high temperature processing techniques (>1400°C) or contamination-prone solution processes [1-2]. Our study reports the growth of InGaZnO nanowires directly from amorphous InGaZnO thin film at 700°C using Mo and Au as bimetal catalyst. The effect of the thickness of Au thin film catalyst on the morphology of the nanowires is also investigated. Amorphous InGaZnO thin films (200 nm) were deposited at room temperature on pre-cleaned Si substrates (1cm x 1cm) via RF magnetron sputtering using sintered (In:Ga:Zn ~2:2:1) targets. Subsequently, Mo (100 nm) and Au (1, 2, 5 nm) thin films were deposited using Electron Beam Evaporation. Annealing was then performed at 700°C for 2h under N2 atmosphere. Shown in Fig. 1a is the IGZO 100 nm Mo/1 nm Au sample annealed at 700°C. Very few and small nanowires were formed, which appeared to be only at the onset of growth. When a thicker Au thin film of 2 nm was used, nanowires of 150-250 nm diameters and 1-5µm lengths grew. However, when a 5 nm Au thin film was deposited, only few nanowires with about the same lengths but with 250-500 nm diameters were formed. This is possibly due to the formation of large nanoparticle catalysts when a thick film is used. Similar to what has been reported in ZnO nanowires, given the same annealing conditions, a higher amount of In, Ga, Zn and O atoms are needed for larger Au particles to reach the supersaturation at the nanoparticle vicinity, which would lead to nanowire growth [3]. The larger diameter formed also suggests that the nanoparticle diameter greatly affects the nanowire diameter. EDX analyses confirmed the composition of the nanowires to be InGaZnO while TEM analysis verified their single crystallinity.