Applied Surface Science 343 (2015) 70–76 Contents lists available at ScienceDirect Applied Surface Science journal h om epa ge: www.elsevier.com/locate/apsusc Effects of substrate temperature on the growth, structural and optical properties of NiSi/SiC core–shell nanowires Najwa Binti Hamzan, Farah Nadiah Binti Nordin, Saadah Abdul Rahman, Nay Ming Huang, Boon Tong Goh ∗ Department of Physics, Faculty of Science, Low Dimensional Materials Research Centre (LDMRC), University of Malaya, 50603 Kuala Lumpur, Malaysia a r t i c l e i n f o Article history: Received 7 December 2014 Received in revised form 10 February 2015 Accepted 4 March 2015 Available online 19 March 2015 Keywords: Core–shell nanowires NiSi SiC Photoluminescence HWCVD a b s t r a c t In this paper we attempt to study the growth of NiSi/SiC core–shell nanowires on Ni-coated glass substrates by hot-wire chemical vapor deposition. The samples were prepared at different substrate temperatures of between 350 and 527 ◦ C to investigate the growth of the nanowires. Ni nanoparticles were used as templates for initially inducing the growth of these core–shell nanowires at substrate tem- perature as low as 350 ◦ C. The high density of the nanowires was clearly demonstrated at higher substrate temperatures of 450 and 527 ◦ C. These core–shell nanowires were structured by single crystalline NiSi and amorphous SiC as the core and shell of the nanowires respectively. The amorphous SiC shell consisted of SiC nanocolumns within an amorphous matrix. The formation of these high density nanowires showed a noticeable suppression in photoluminescence emissions from the oxygen-related defects and superior optical absorption in visible and limited near infrared regions. The effects of substrate temperatures on growth, optical and structural properties of the nanowires are presented and discussed. © 2015 Elsevier B.V. All rights reserved. 1. Introduction Of late one-dimensional (1D) hybrid heterostructures or core–shell nanowires have assumed much importance especially in energy conversion and storage applications due to their enhanced properties as compared to both single-phased materials alone [1–3]. The single-phased intrinsic materials generally have low con- ductivity, week mechanical stability and associated side reactions due to their unprotected surfaces, which make them unsuitable for various device applications [4,5]. Owing to the extremely large sur- face area of the 1D hybrid heterostructures, core–shell nanowires have been widely used in electrochemical energy storage and conversion applications [6–8]. For example, Cui and co-workers reported that a crystalline core-amorphous shell Si nanowire design has shown significant enhancement in the capacity/power rate and efficiency in lithium-ion batteries and solar cells respec- tively [9]. Moreover, Lee et al. [10] demonstrated a significant improvement in light absorption and photocatalytic capability of ZnO/Si hierarchical core–shell heterostructures. In addition, the core–shell heterostructures also are favorable for various opto- electronic applications. Lauhon demonstrated an enhancement of ∗ Corresponding author. Tel.: +60 3 79674147; fax: +60 3 79674146. E-mail address: boontong77@yahoo.com (B.T. Goh). carrier mobility in a coaxial FET fabricated by the modulation doped core–shell structures [11]. Recently, high band gaps in the shell nanowires have been reported as acting as a passivation barrier to suppress the interaction of carriers with the surface states which generally degraded the PL emission intensity [12–14]. SiC nanowires are well known for their superior properties of high mechanical stability, good chemical resistivity, high ther- mal stability, high thermal conductivity, and adjustable electric conductivity [15–17]. These versatile properties have made them suitable for various applications such as in field effect transistors [18], field emitters [19] and nano electromechanical devices [20]. The incorporation of single-crystalline NiSi nanowires as core–shell nanowires is expected to enhance the properties of this 1D het- erostructure. Moreover, the highly metallic properties of the NiSi could allow for their use as 1D electrode for enhancing the effi- ciency of electron transfers between current collector supports and individual electrode materials [21,22]. On the other hand, a low temperature growth of NiSi nanowires could also provide a new opportunity for the deposition of this heterostructure on a flexible substrate. In this work, NiSi/SiC core–shell heterostructure nanowires were prepared by hot-wire chemical vapor deposition (HWCVD). Among the various deposition techniques, HWCVD is one of the most promising for its low-temperature, high deposition rate and large-area deposition of SiC-based thin film materials [23–25]. http://dx.doi.org/10.1016/j.apsusc.2015.03.023 0169-4332/© 2015 Elsevier B.V. All rights reserved.