Determination of electronic properties of Al/p-Si/composite organic semiconductor (MIOS) junction barrier by current–voltage and capacitance–voltage methods

The junction properties of Al/p-Si/DB6MEH diode have been investigated by current–voltage and capacitance–voltage methods. The n ideality factor of Al/p-Si/DB6MEH diode was obtained to be 1.92, which is higher than unity, indicating metal–insulator–organic layer-semiconductor configuration rather than an ideal Schottky diode. The effect of series resistance was analyzed by Cheung functions. The series resistance RS values were determined from dV/d ln I–I and H(I)–I plots and were found to be 19.55 kΩ and 20.44 kΩ, respectively. The shape of the interface state density is in the range of ESS 0.53–0.69 eV. The ϕb (0.93 eV) value obtained from C–V measurement is higher than that of the ϕb (0.75 eV) value obtained from I–V measurement. The discrepancy between these values is probably due to existence of excess capacitance at the structure or presence of barrier inhomogeneities. The ideality factor and barrier height values for the Al/p-Si/DB6MEH junction at the room temperature are significantly larger than that of the conventional Al/p-Si Schottky diode. It is evaluated that the DB6MEH organic layer controls electrical charge transport properties of Ag/p-Si diode by excluding effects of the SiO2 residual oxides on the hybrid diode.