A tandem solar cell in a mechanical (stack like) arrangement of gallium arsenide and silicon solar cells is evaluated as a pathway towards higher efficiency terrestrial solar cells. In this work the technical feasibility of the tandem solar cell is investigated. Here we report on detailed electrical and optical simulations of this structure quantifying various theoretical and practical loss mechanisms in the interface and in the device and indicate that an efficiency improvement of 5.13% would be attainable with the present generation of gallium arsenide and silicon solar cells in this configuration. The optical and electrical parameters for gallium arsenide and silicon simulation models were extracted from experimental devices and material vendors. The developed simulation models were validated by comparing the performance of standalone gallium arsenide and silicon solar cells with experimental devices reported in the literature. (C) 2013 Elsevier Ltd. All rights reserved.