Study on the role of filament temperature on growth of indium-catalyzed silicon nanowires by the hot-wire chemical vapor deposition technique Su Kong Chong a, * , Boon Tong Goh a , Chang Fu Dee b , Saadah Abdul Rahman a a Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia b Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, Malaysia highlights < Threshold filament temperature for successive growth of SiNWs is between 14001500  C. < Catalytic effect of indium particles is enhanced by removes their native oxide layer. < Growth rate of SiNWs is related to the desorption rate of Si radicals. < Increase in filament temperature can improve the crystallinity of the SiNWs. article info Article history: Received 17 July 2011 Received in revised form 11 May 2012 Accepted 11 May 2012 Keywords: Nanostructures Chemical vapor deposition (CVD) Crystal growth abstract Silicon nanowires (SiNWs) were synthesized from indium catalysts on the Si(111) substrate using the hot-wire chemical vapor deposition technique. A tungsten filament with purity of 99.95% was employed for both the evaporation of an indium wire as catalyst and the decomposition of the precursor gas silane diluted in hydrogen. In this study, we investigated the role of the filament temperature (T f ) on the growth and structural properties of the SiNWs. A threshold T f for the successive growth of the SiNWs via a vapor- liquid-solid process was observed at T f between 1400 and 1500  C. For T f of 1400  C and below, only a layer of Si shell cladding was formed on the indium core. An increase in T f above the threshold resulted in a significant increase in the number density and the aspect ratio of the SiNWs. X-ray diffraction and micro-Raman measurements indicated an enhancement in crystallinity of the SiNWs with the increase in T f . Fourier transform infrared analysis showed an enhancement in the presence of SieO and SieH related bonds with the increase in T f . The SieO bond is mostly originated from the native oxide layer of SiNWs, while SieH bond suggests that SieH x species were responsible for the growth. Ó 2012 Elsevier B.V. All rights reserved. 1. Introduction One-dimensional silicon nanowires (SiNWs) have attracted considerable interest due to their wide range of possible applica- tions in nanoelectronic, photonic, biomedical, solar energy har- vesting, and thermoelectronic devices [1e3]. Extensive studies on the growth and the fundamental properties of the SiNWs based on numerous deposition techniques including laser ablation, chemical vapor deposition (CVD), lithography and thermal evaporation of SiO x powder, have been investigated and documented [4e6]. Despite these techniques, low temperature CVD techniques, such as plasma enhanced chemical vapor deposition (PECVD) and hot-wire chemical vapor deposition (HWCVD) are currently being preferred for the fabrication of SiNWs due to the lower production cost and large-scale production capability, making these methods more attractive for industrial applications. Besides the advantages of low- temperature growth processes in PECVD and HWCVD of SiNWs, these techniques have been proven to enhance the growth rate of SiNWs [7,8]. In PECVD, ions play an important role in surface bombardment effects, which create the formation of SieH networks for assisting the growth of SiNWs. However, several studies on this subject have reported adverse effects of ion bombardment on the crystallinity of the samples [9,10]. Thus HWCVD, which provides an ion-free deposition by catalytical decomposition of the source gas using a catalyzer, usually tungsten, is comparatively a better tech- nique for the growth of SiNWs. Recent studies on HWCVD grown SiNWs [11e 14] demonstrated that HWCVD is a promising technique for the growth of novel one-dimensional Si nanostructures. In HWCVD processing, the filament temperature (T f ) is consid- ered an important parameter since it directly affects the * Corresponding author. Tel.: þ60 3 79674147. E-mail address: sukong1985@yahoo.com.my (S.K. Chong). Contents lists available at SciVerse ScienceDirect Materials Chemistry and Physics journal homepage: www.elsevier.com/locate/matchemphys 0254-0584/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2012.05.037 Materials Chemistry and Physics 135 (2012) 635e643