Single Crystal, High Band Gap CdS Thin Films Grown by RF Magnetron Sputtering in Argon Atmosphere for Solar Cell Applications

Authors Rupali Kulkarni1, Amit Pawbake1 , Ravindra Waykar1 , Ashok Jadhawar1 , Haribhau Borate1 , Rahul Aher1 , Ajinkya Bhorde1 , Shruthi Nair1, Priyanka Sharma1 , Sandesh Jadkar2

1School of Energy Studies, Savitribai Phule Pune University, 411007 Pune, India

2Department of Physics, Savitribai Phule Pune University, 411007 Pune, India

Issue Volume 10, Year 2018, Number 3
Dates Received 01 March 2018; revised manuscript received 09 June 2018; published online 25 June 2018
Citation Rupali Kulkarni, Amit Pawbake, Ravindra Waykar, et al., J. Nano- Electron. Phys. 10 No 3, 03005 (2018)
PACS Number(s) 81.15.Cd, 81.07.Bc
Keywords CdS films, RF magnetron sputtering (5) , Low angle XRD (2) , Raman spectroscopy (18) , EDX spectroscopy.

Single crystal thin films of CdS were grown onto glass substrates by RF magnetron sputtering at various substrate temperatures. Structural, optical and morphology properties of these films were investigated through low angle XRD, Raman spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, UV-Visible spectroscopy etc. Formation of single crystal CdS films has been confirmed by low angle XRD and Raman spectroscopy analysis. Low angle XRD showed that CdS films has preferred orientation in (111) direction. Improvement of crystallinity and increase in average grain size of CdS crystallites has been observed with increase in substrate temperature. Surface morphology investigated using SEM showed that CdS films deposited over entire range of substrate temperature are highly smooth, dense, homogeneous, and free of flaws and cracks. The EDX data revealed the formation of high-quality nearly stoichiometric CdS films by RF magnetron sputtering. Furthermore, the CdS films deposited at low substrate temperatures (( 200 0C) are slightly S rich while deposited at higher substrate temperatures (( 200 0C) are slightly Cd rich. The UV-Visible spectroscopy analysis showed that an average transmission ~ 80-90 % in the visible range of the spectrum having band gap ~ 2.28 -2.38 eV, which is quite close to the optimum value of band gap for a buffer layer in CdTe/CdS, Cu2S/CdS hetero-junction solar cells.

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