Space charge limited current-voltage characteristics of organic semiconductor diode fabricated at various gravity conditions

In this paper, temperature-dependent current-voltage (I-V) characteristics of poly-N-epoxipropyl carbazole (PEPC) are evaluated. The PEPC is doped with anthracene (An) and deposited on nickel (Ni) substrate with a centrifugal machine. The films are grown at room temperature but at varying gravity conditions, such as 1g, 123g, 277g and 1107g, where g is acceleration due to gravity. It is demonstrated that the space charge created by the trapped charges controls the device's characteristics. Thus, by employing trapped space charge limited current model, charge transport parameters are estimated and discussed as a function of ambient temperatures. It is learned that the trap factor, free carrier density, effective mobility and trap density are quasi-linear functions of temperatures. It is shown that devices fabricated at 277g exhibit superior electrical properties compared to 1g, 123g and 1107g devices. It has been demonstrated that an organic semiconductor device performance could be enhanced by optimizing its fabrication parameters. (C) 2009 Elsevier B.V. All rights reserved.