Pulsed electrodeposition of Cu2ZnSnS4 absorber layer precursor for photovoltaic application

Publication date: Available online 15 January 2016
Source:Thin Solid Films
Author(s): Sushmita Chaudhari, Palli Srinivas, P.K. Kannan, Suhash Ranjan Dey
Cu2ZnSnS4 (CZTS), comprising of earth abundant and non-toxic elements, is an ecofriendly and cost effective thin film absorber layer for solar cell applications. The present work describes the fabrication of p-type absorber material Cu2ZnSnS4 (CZTS) from alkaline pyrophosphate solution through pulsed electrodeposition (PED) at room temperature. CZTS thin film is prepared from one step co-electrodeposited Cu-Sn-Zn (CZT) precursor film obtained from pyrophosphate bath under potentiostatic condition (−1.4V) onto a Ni substrate followed by annealing in sulfur atmosphere at 500 °C for 1h 30min. To achieve the desired CZTS stoichiometry in the deposited material, applied potential for the co-deposition has been calculated from the Tafel plots. The crystallographic phases, morphology and composition of the electrodeposited Cu-Sn-Zn precursor and the sulfurized films are assessed through X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. Formation of CZTS phase is confirmed from X-ray diffraction and Raman Spectroscopy of the sulfurized sample. Optical band gap measurement is investigated by using UV–Vis absorption spectroscopy. The CZTS thin film of kesterite structure is obtained with band gap of 1.5eV, which is suitable for solar cell fabrication.