Characterization of Tin-catalyzed silicon nanowires synthesized by the hydrogen radical-assisted deposition method
Introduction
Since the synthesis of carbon nanotubes [1], much attempt has been devoted to synthesizing one-dimensional nanostructure materials, such as nanowires, nanorods, nanotubes and nanoribbons [2]. These nanomaterials provide a good system to research the dependence of electrical, optical and magnetic properties [3], [4], [5], [6], [7], [8]. They are also expected to play an important role as both interconnections and functional units in fabrication of electronic, optoelectronic and electrochemical devices with low-dimensional structures. In recent years, silicon nanowires (SiNWs) as one-dimensional structure have attracted due to their unique mechanical and semiconducting properties. SiNWs have been synthesized by using various methods, such as chemical vapor deposition (CVD) [9], oxide-assisted [10], template-assisted [11] and laser ablation method [12] via well-known vapor–liquid–solid (VLS) mechanism [9], [13]. Moreover, various metal nanoparticles, such as Au, Al, Ga, Ti and Sn [9], [14], [15], [16], [17], have been studied for synthesizing SiNWs. Among these, tin (Sn) appears to be the favorable catalyst for low temperature synthesis from its phase diagram, because the Sn–Si alloy has relatively low eutectic temperature as 232 °C [18]. The low melting point materials form eutectic with silicon at low temperature and with extremely low content of the elemental semiconductors. We have also reported a simple way to synthesize SiNWs using the low-melting-point metal catalysts, such as In and Ga, by the hydrogen radical-assisted deposition method [19], [20]. In particular, the synthesis of SiNWs with Sn catalyst, which has relatively low eutectic temperature with Si, has been reported by a few researchers [17], [21]. Moreover, their properties are not well-known yet. In this study, therefore, the SiNWs are synthesized using Sn nanoparticles as catalyst at various growth conditions and their characteristics are investigated.
Section snippets
Experimental
Tin (Sn) metal thin film as catalyst is evaporated on Corning #1737 glass substrates. Before metal film evaporation, the glass substrates are cleaned in a bath containing acetone, ethanol and deionized water with ultrasonic agitation for 5 min. The substrates are located in vacuum chamber and Sn metal film approximately 100 nm is deposited. The Sn-coated glass substrates are set and heated at 400 °C in the experimental vacuum chamber with a pressure of 2 × 10− 5 Torr. Hydrogen (H2) gas is
Results and discussion
Before synthesis of silicon nanowires (SiNWs), hydrogen radical treatment is performed on the Sn-coated substrate to fabricate Sn nanoparticles. The hydrogen radical treatment is effective to obtain voluminous SiNWs. Subsequently, the SiNWs were synthesized at various hydrogen (H2) gas flow rates. In order to investigate the morphological property of as-synthesized SiNWs at varied conditions, a FE-SEM observation was performed after synthesis of SiNWs for 10 min at 400 °C.
Fig. 1 (a)–(c) shows
Conclusion
Tin-catalyzed silicon nanowires (SiNWs) were synthesized at various hydrogen gas flow rates using the hydrogen radical-assisted deposition method. Voluminous SiNWs, which have various crystal phases, were whisker-likely synthesized at all growth condition. Their structures were gradually changed with increasing hydrogen gas flow rate. The diameters of SiNWs on the bottom side were increased ranging from approximately 50 to 200 nm and their lengths extended up to ~ 2 µm. It indicates that the
References (21)
- et al.
J Ind Eng Chem
(2008) - et al.
Chem Phys Lett
(1999) J Cryst Growth
(1975)- et al.
Nat Nanotechnol
(2006) - et al.
Mater Lett
(2008) Nature
(1991)Nanowires and Nanobelts: Materials, Properties and Devices
(2003)- et al.
Jpn J Appl Phys
(1997) Science
(1996)- et al.
Science
(2001)
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