Microphase separation of A-b-B diblock copolymer brushes in selective solvents is investigated by single-chain-in-mean-field (SCMF) simulations. Depending on the solvent selectivity of the blocks, the fraction (f) of the A block, and the grafting density (sigma), perpendicular segregation, lateral segregation, or their combination occurs. Using extensive simulations, we obtain morphology diagrams in terms of f and sigma for block copolymer brushes in different solvents. The morphologies of nanoscopic domains lack long-range order, and they are analyzed using integral geometry techniques.