RISE AND DECAY TIME KINETICS OF PHOTOCURRENT IN MEROCYANINE DYES

The dependence of rise and decay time of photocurrent on the applied v oltage, sample temperature and incident light intensity has been studi ed for a new series of merocyanine dyes (six in numbers). The samples were prepared in thin film form on a multi-electrode raster type surfa ce cell by vacuum deposition. Two orders of magnitude difference was f ound in the photocurrent when the samples were studied in air and vacu um of the order of 10(-5) Torr in the conductivity cell. Rise and deca y times were found to be less in vacuum. At higher temperatures, the p hotocurrent more rapidly approaches its stationary value because the r atios of concentrations of filled traps and free carriers (n(t)/pt and p(t)/p) decrease as the temperature is increased. The dyes were found to behave as p-type semiconductors.