Study on the basic capacitance–voltage characteristics of organic molecular semiconductors

Abstract Capacitance–voltage ( C – V ) characteristics of organic molecular semiconductors attracted much research interest recently, but no convincing physical mechanism has been established so far. In this work, the C – V characteristics of pentacene-based devices have been systematically investigated at various frequencies. Only one peak occurs when the measuring frequency is less than 3 kHz or greater than 8 kHz. While within the frequency range between the two, two C – V peaks are observed with quite different dependence on temperature, which suggests that the origins of these two C – V peaks are respectively mobile holes and trapped carriers. This conclusion is also experimentally validated with the C – V characteristics of intentionally doped devices.