Admittance spectroscopy of CuPC-Si and CoPC-Si heterostructures

The electronic properties of the interface between n-type Si and metallophthalocyanines (MPcs) have been investigated. Films of MPc (M = Co, Cu), with a thickness of 350 nm, were deposited at room temperature by thermal evaporation and subsequently subjected to heat treatment in air at the temperature range 293-500 K. The variation in the capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of the Al/MPc/n-Si/Al Schottky barrier devices have been systematically investigated as a function of frequencies in the frequency range of 42 Hz-5 MHz at different temperatures in the range of 210-473 K. The effects of density of interface states (Nss) and series resistance (Rs) on I-V, C-V and G-V characteristics were investigated. The high-frequency capacitance (Cm) and conductance (Gm) values measured under reverse bias were corrected to decrease the effects of series resistance. Those results show that the locations of interface states between n-Si/MPc and series resistance have a significant effect on electrical characteristics of the Al/MpC/n-Si SB devices.