Nilija Sukumaran¹, Elilan Yogenthiran¹, Shivatharsiny Yohi^1*, Suvanya Amirthalingam² and Thanihaichelvan Murugathas²

                       ¹ Department of Chemistry, University of Jaffna, Jaffna, Sri Lanka

                                     ²Department of Physics, University of Jaffna, Jaffna, Sri Lanka

                                                           *yshiva@univ.jfn.ac.lk

 

Abstract

The utilization of toxic chemicals for the synthesis of nanoparticles has limited its application in the field of nanotechnology. The use of natural precursors in the nanoparticle synthesis has opened new paths in the field of nanotechnology to overcome the above strategy. Semiconducting nanoparticles, such as CdS, ZnS and CdSe are prominent materials in optoelectronic applications due to their dimension and less photo corrosion. Among these materials CdS Nanoparticles are highly preferred due to their excellent thermal and chemical stability and tunable bandgap. Generally, CdS Nanoparticles can be synthesized by micro emulsion, ultrasonic irradiation, sol-gel, and photo-itching methods. However, these methods are not cost-effective and environmentally friendly. Therefore, there is a need to synthesize these colloidal nanoparticles using greener approach.

In our study, CdS colloidal nanoparticles were synthesized by utilizing natural resources, such as tobacco, garlic and onion extracts since these plant extracts are the good sources for cadmium (Cd²⁺) and sulphide (S^2-) ions. The green synthesized CdS colloidal nanoparticles were structurally and optically characterized using X-ray diffraction (XRD) and UV-Visible spectroscopies and compared with the chemically synthesized CdS colloidal nanoparticles. These characterizations confirmed the presence of CdS colloidal Nanoparticles in both greener and chemical systems. Finally, the semiconducting property of both of these colloidal CdS Nanoparticles were compared by fabricating a colloidal thin film field effect transistor (FET) on a 100 nm SiO₂ coated Si substrate using Pt as source and drain electrodes. The channel length of the fabricated was 2 µm and widths is 2 mm. The electrical properties of FETs were studied using computer interfaced course measure unit. The non-linearity in the I-V curves is observed in all the colloidal thin film FETs. The FETs from (G1) showed better semi conductivity when compare to the FETs from (G1).This confirmed that the greener synthesized CdS colloidal nanoparticles  are semiconducting and Hence, they could apply to several optoelectronic applications.

Keywords: Green synthesis: Conductivity; Semiconductor; Colloidal; FET

 

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