Carrier Transport Investigation on Organic Semiconductor by Electrical DC and AC Measurements: the Case of Alq3


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In the present work, the nature of the electrical mechanism for carrier transport in Alq3 is studied by current-voltage measurements and broadband dielectric spectroscopy. The d.c. currentvoltage characteristics at low applied electrical field exhibits a classical “N” shape due to interfacial states located at metal-organic interface, but tend to disappear when successive higher forward bias is applied. Using dielectric spectroscopy it is possible to observe that the main relaxation peak shifts to a higher frequency with the increase of the applied d.c. voltage (from approximately 100 Hz with 0 V d.c. bias to approximately 400 Hz with 6 V d.c. bias) indicating a semiconductor structure change. The logarithmic Z’’ vs. Z’ plot has a slope about 0.7 that decreases to 0.5 with the increasing applied d.c. voltage, reaching a classic Debye relaxation. An attempt to correlate with some structural changes is made.



Materials Science Forum (Volumes 514-516)

Edited by:

Paula Maria Vilarinho




V.M. Silva et al., "Carrier Transport Investigation on Organic Semiconductor by Electrical DC and AC Measurements: the Case of Alq3", Materials Science Forum, Vols. 514-516, pp. 78-82, 2006

Online since:

May 2006




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