We have investigated the mechanism of direct electron-beam writing in thin films of passivated gold nanoclusters. The exposure of films of approximately monolayer thickness (6 nm) was investigated as a function of electron dose on various substrates. Films were obtained on various substrates: graphite, silicon, thermally grown silicon dioxide and sputtered silicon dioxide. The experimental results are compared with Monte Carlo simulations of the electron scattering. We conclude that, in the case of such monolayer films, exposure of the clusters is dominated by electrons scattered in the substrate, so that the properties of the resist depend strongly on the nanocluster/substrate combination. (C) 2001 American Institute of Physics.