It is well established that the inclusion of a high-low junction at the back of a solar cell or the so-called back surface field (BSF), improves its performance. In the other hand, if the same structure is placed at the front of the cell as high-low junction emitter, front surface field (FSF), a notable amelioration is observed. In this work, a simulation of the influence of the FSF on GaAs solar cell spectral response and photocurrent is carried out. The model is based on a simple analytical approach. The most important role of an FSF layer is the enhancement of light-generated free carriers' collection, and this property is primarily responsible for the increase of the short-wavelength quantum efficiency. This is achieved by the drastic reduction of the effective recombination at the emitter upper boundary. The effects of the FSF layer doping concentration and its thickness on the cell performance are discussed by using the computed results. (c) 2008 Elsevier B.V. All rights reserved.