We have investigated the characteristics of transparent metal-insulator-semiconductor field-effect transistors (MISFETs) fabricated using InGaO3(ZnO)(m) (m = integer) single-crystalline thin films as n-channel layers and amorphous alumina as gate insulator films. The MISFETs exhibit good characteristics such as insensitivity to visible light illumination, off-current as low as similar to1 nA with a positive threshold voltage of similar to3 V and on/off current ratio of 10(5). The field-effect mobility increased from similar to1 to similar to10 cm(2) (V s)(-1) as the m-value increased. Room temperature Hall mobility also increased. However, unexpectedly these values were lower than the field-effect mobility. It is explained by existence of shallow localized state in the homologous compounds. (C) 2003 Elsevier B.V. All rights reserved.