Regular Article

Numerical study of the influence of ZnTe thickness on CdS/ZnTe solar cell performance^*

¹ Laboratoire de Physique de l’Atmosphère et Modélisation (LPAM), Université Hassan II, Faculté des Sciences et Techniques, BP 145 Mohammedia, Morocco
² Departament de Física Aplicada--ETSED, Universitat Politècnica de València, Camí de Vera s/n 46022 València, Spain

^a e-mail: elmanouni123@gmail.com

Received: 17 July 2015
Revised: 30 August 2015
Accepted: 2 September 2015
Published online: 3 May 2016

Abstract

At present most of II–VI semiconductor based solar cells use the CdTe material as an absorber film. The simulation of its performance is realized by means of various numerical modelling programs. We have modelled a solar cell based on zinc telluride (ZnTe) thin film as absorber in substitution to the CdTe material, which contains the cadmium element known by its toxicity. The performance of such photovoltaic device has been numerically simulated and the thickness of the absorber layer has been optimized to give the optimal conversion efficiency. A photovoltaic device consisting of a ZnTe layer as absorber, CdS as the buffer layer and ZnO as a window layer was modelled through Solar Cell Capacitance Simulator Software. Dark and illuminated I-V characteristics and the results for different output parameters of ZnO/CdS/ZnTe solar cell were analyzed. The effect of ZnTe absorber thickness on different main working parameters such as: open-circuit voltage V_oc, short-circuit current density J_sc, fill factor FF, photovoltaic conversion efficiency η was intensely studied in order to optimize ZnTe film thickness. This study reveals that increasing the thickness of ZnTe absorber layer results in higher efficiency until a maximum value and then decreases slightly. This maximum was found to be 10% at ZnTe optimum thickness close to 2 µm.