High Band Gap Nanocrystalline Tungsten Carbide (nc-WC) Thin Films Grown by Hot Wire Chemical Vapor Deposition (HW-CVD) Method

Authors Bharat Gabhale1, Ashok Jadhawar1 , Ajinkya Bhorde1 , Shruthi Nair1 , Haribhau Borate1 , Ravindra Waykar1 , Rahul Aher1 , Priyanka Sharma1 , Amit Pawbake1*, Sandesh Jadkar2

1School of Energy Studies, Savitribai Phule Pune University, 411 007 Pune, India

2Department of Physics, Savitribai Phule Pune University, 411 007 Pune, India

Е-mail sandesh@physics.unipune.ac.in
Issue Volume 10, Year 2018, Number 3
Dates Received 01 March 2018; revised manuscript received 09 June 2018; published online 25 June 2018
Citation Bharat Gabhale, Ashok Jadhawar, Ajinkya Bhorde, et al., J. Nano- Electron. Phys. 10 No 3, 03001 (2018)
DOI https://doi.org/10.21272/jnep.10(3).03001
PACS Number(s) 81.15.Cd, 81.07.Bc
Keywords WC films, HW-CVD (2) , Low angle XRD (2) , Raman spectroscopy (18) , XPS (4) .

In present study nanocrystalline tungsten carbide (nc-WC) thin films were deposited by HW-CVD using heated W filament and CF4 gas. Influence of CF4 flow rate on structural, optical and electrical properties has been investigated. Formation of WC thin films was confirmed by low angle XRD, Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) analysis. Low angle XRD analysis revealed that WC crystallites have preferred orientation in (101) direction and with increase in CF4 flow rate the volume fraction of WC crystallites and its average grain size increases. Formation of nano-sized WC was also confirmed by transmission electron microscopy (TEM) analysis. UV-Visible spectroscopy analysis revealed increase in optical transmission with increase in CF4 flow rate. The WC film deposited for 40 sccm of CF4 flow rate show high transparency (( 80-85 %) ranging from visible to infrared wavelengths region. The band gap shows increasing trend with increase in CF4 flow rate (3.48-4.18 eV). The electrical conductivity measured using Hall Effect was found in the range ( 103-141 S/cm over the entire range of CF4 flow rate studied. The obtained results suggest that these wide band gap and conducting nc-WC films can be used as low cost counter electrodes in DSSCs and co-catalyst in electrochemical water splitting for hydrogen production.

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