Growth of ZnO and ZnMgO layers by molecular beam epitaxy was conducted toward biosensing application. Oxygen polar (-c) ZnO layers were grown with oxygen termination, while irradiation of Zn beam made the Zn-terminated surface. Luminescent energy of ZnMgO shifted as high as 3.65 eV by increasing Mg composition. Electron carrier densities and mobilities of ZnO and ZnMgO were around 3 x 10(17) cm(-3) and 100 cm(2)/V s, respectively. (C) 2002 Elsevier Science B.V. All rights reserved.