Non-linear I-V characteristics of MEH-PPV patterned on sub-micrometer electrodes

A sub-micrometer-wide line of a conjugated polymer MEH-PPV [poly(2-methoxy- 5(2-ethyl hexyloxy)-p-phenylene vinylene)] was patterned using a scanning e lectron microscope (SEM). The spin-coated thin MEH-PPV film was exposed to the electron beam in SEM, resulting in an increase in cross-linking, which reduced the solubility of the MEH-PPV film. The polymer was developed in p- xylene to dissolve the non-irradiated part of the polymer. The width, lengt h and thickness of the active patterned area, determined by the atomic forc e microscopy (ATM) image, was 500, 200 and 20 nm, respectively. The two-pro be current-voltage characteristics of the patterned MEH-PPV line were measu red as a function of temperature. The higher field data of the non-linear I -V curves were fitted using the single carrier device model which considere d the field and temperature dependent mobility with space charge limited co nduction (SCLC). The estimated zero-field hole mobility was of the order of 10(-3) cm(2)/Vs with an activation energy of 0.038 eV. (C) 2001 Elsevier S cience B.V. All rights reserved.