Dielectric relaxation and AC conductivity behaviour of Se80Te15Bi5/PVA nanocomposite film

An analytical approach has been applied to investigate the dielectric properties and ac conductivity behaviour of a new polymer nanocomposite (PNC) of polyvinyl alcohol (PVA) doped with nanocolloids of Se80Te15Bi5 glass over a frequency range of 100 Hz-5 MHz for temperatures ranging from 298 K to 448 K. An increase in dielectric constant and relaxation time for PNC has been seen as compared to pure PVA. The Cole-Cole model of relaxation shows good agreement with experimental data. The ac conductivity (sigma(ac)) behaviour has been found to follow the Jonscher's power law A omega(s). Prevailing mechanism of conduction has been confirmed to be correlated barrier hopping (CBH) type. The synthesized PNC has been used as an active layer in the fabrication of a memory device. Electrical characterization of the device has been done by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The switching between high conductive (ON) and low conductive (OFF) states of the device may be attributed to charge trapping and de-trapping in Se80Te15Bi5 nanocolloids. The retention characteristic of the device, determined by capacitance-time (C-t) measurements indicates its good reliability and stability.