Role of Injection Barrier in Capacitance-Voltage Measurements of Organic Devices

• Published in: IEEE electron device letters Vol. 35; no. 5; pp. 581 - 583
• Main Authors: Nigam, Akash, Nair, Pradeep R., Premaratne, Malin, Rao, V. Ramgopal
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.05.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Capacitance; Cutoff frequency; Doping; Electronics; Exact sciences and technology; Injection Barrier; Organic field effect transistor; Pentacene; Physics; Semiconductor device measurement; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors; Voltage measurement; Pentacene; Capacitance; Organic field effect transistor; Injection Barrier; Field effect transistor; Response time; Doping; Organic semiconductors; Numerical simulation; Voltage capacity curve; Organic electronics; Charge carrier injection
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2014.2313411

Capacitance-voltage (C-V) measurements represent a very useful technique, however, its usage in organic devices has been a subject of debate because of the role played by the ambient-induced unintentional doping. In this letter, we show that, contrary to the current understanding, prolonged ambient exposure does not significantly increase the unintentional doping density of organic semiconductors (OSCs). Our C-V measurements and detailed numerical simulations clearly indicate that the observed dispersion in C-V characteristics can be attributed to the variation in the carrier injection barrier at the OSC/electrode interface. An analytical relation between the injection barrier and the response time is derived to describe the C-V characteristics of organic devices.