Photovoltaic properties of sintered all-polycrystalline CdS/CdTe and Cd0.94Zn0.06S/CdTe solar cells have been investigated by varying cell width to maximize solar cell module efficiency. Short-circuit current density, fill factor and efficiency of the solar cells degrade with increasing cell width. Series resistance of the solar cells increases with the cell width resulting in the degradation of solar cell efficiency. Sintered Cd1-xZnxS/CdTe solar cells with a cell width of 4 mm showed the maximum module efficiency. Sintered CdS/CdTe and Cd0.94Zn0.06S/CdTe solar cells with a cell width of 4 mm showed efficiency of 10.0% and 11.0% under solar illumination with an intensity of 85 mW cm-2. The estimated values of the module efficiency were 6.7% and 7.3%, respectively. The reduction in efficiency for cell width greater than 4 mm is attributed to the resistance of the Cd1-xZnxS layer.