We report a nonvolatile, write-once-read-many-times (WORM) memory device based on a simple organic-inorganic heterojunction. The organic-based hybrid used is 9,9-dihexylfluorene and Eu-complexed benzoate, which contains both electron-donor (9,9 ''-dihexylfluorene) and electron-acceptor (europium complex) groups. Under current-voltage testing, the device is able to switch from one initial nonconducting state to a conducting state once a threshold voltage is reached. Diode rectifying characteristics, with a current ratio of four orders of magnitude, is also observed after the device is turned on, which is essential to address one memory cell in large passive matrix circuits. (c) 2007 The Electrochemical Society.