Observation of charge behavior in organic photoconductor using the pulsed electroacoustic method and pressure wave propagation method

Recently, many methods to measure the space charge distribution in solid dielectrics have been developed, such as the laser-induced pressure wave propagation (LIPP) method by means of the pulse laser, the pressure wave propagation (PWP) method by means of the piezo-electric transducer, and the pulsed electroacoustic (PEA) method. In this report, the resolution of PWP method using a piezo-electric transducer as a generator of acoustic pulse wave has been improved. To improve the resolution, a new technique to generate the narrow acoustic wave was employed. In consequence of the usage of this new technique, we have succeed to obtain the resolution of about 10 μm. The principle and the result of this technique will be introduced here. Furthermore, a typical measurement result of carrier generation, drift and trapping in an organic photoconductor (OPC) will be introduced and compared with the result obtained using PEA method