Large-size single crystals of beta-Ga2O3 with 1 inc in diameter have been grown by the floating zone technique. The stable growth conditions have been determined by the examination of the crystal structure. Wafers have been cut and fine polished in the (100), (010) and (001) planes. These were highly transparent in the visible and near UV, as well as electrically conductive, indicating the potential use of beta-Ga2O3 as a substrate for optoelectic devices operating in the visible/near UV and with vertical current flow. (C) 2004 Elsevier B.V. All rights reserved.