Theoretical study of the adsorption of 0.75 and 1 monolayer of F, Cl, and I on the Ge(0 0 1)-p(1 x 2) surface is presented. Various stable atomic configurations are considered, their surface electronic properties are discussed by means of the density-of-states analysis, and the corresponding STM images are simulated. While the results obtained for Cl and I are similar to those known for Br, the F-covered surfaces exhibit noticeably different features. (C) 2010 Elsevier B. V. All rights reserved.