Characterization of undoped ZnO layers grown by molecular beam epitaxy towards biosensing devices

Undoped ZnO layers grown by molecular beam epitaxy (MBE) were investigated aiming at biosensing devices based on organic/inorganic hybrid structures. Clear observation of free exciton emission in low temperature photoluminescence (PL) spectra and electron mobility as high as 114 cm(2)/Vs at room temperature indicate that the quality of the ZnO layers is applicable for biosensors. Surface bonding of the ZnO the layers, which is one of the key issues for hybridization, was examined by means of xray photoelectron spectroscopy (XPS). The XPS spectra of O Is revealed that formation and desorption of hydroxyl (OH) bonds can be controlled by air exposure and thermal treatments. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.