The nonpolymeric organic compound (pyronine-B)/p-type silicon/Sn contact barrier devices

The nonpolymeric organic compound pyronine-B film on a p-type Si substrate has been formed by means of the process of adding a solution of pyronine-B in methanol and evaporating the solvent. It has been seen that the pyronine-B/p-Si contact shows the rectifying behaviour and the reverse curves exhibit the excellent saturation. The barrier height and ideality factor values of 0.65 eV and 1.51, respectively, for this structure have been obtained from the forward bias current-voltage (I-V) characteristics. The energy distribution of the interface states in the inorganic semiconductor bandgap and their relaxation time in the energy range (0.41-E-v) to (0.65-E-v) eV have been determined from the low-capacitance-frequency (C-f) characteristics. The measurement frequency ranges from 50 Hz to 2 MHz. The low and intermediate frequency regions approximately range 50-700 Hz and 700 Hz-500 kHz, respectively. It has been seen that the interface state density has an exponential rise with bias from the midgap towards the top of the valence band. The relaxation time shows a slow exponential rise from the top of the valence band towards the midgap with the applied voltage. (C) 2002 Elsevier Science B.V All rights reserved.