GaAs(001)c(4X4) surfaces were obtained in the 380-450 degrees C temperature range by thermal desorption of As cap layers from substrates prepared by molecular beam epitaxy. Although reflection high-energy electron diffraction patterns showed little change in the temperature range explored, in situ scanning tunneling microscopy and Auger spectroscopy, complemented by ex situ atomic force microscopy, indicate that in the lower-temperature range examined up to 11%-12% of the surface may still be occupied by adsorbed As in the form bf wires and particles preferentially oriented along[100] directions.