Electrical properties and conduction mechanism of an organic-modified Au/NiPc/n-InP Schottky barrier diode

The effect of nickel phthalocyanine (NiPc) organic interlayer on the electronic parameters of Au/n-InP Schottky contacts has been investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements. Measurements showed that the barrier heights and ideality factors are 0.58 eV (I-V), 0.69 eV(C-V) and 1.32 for Au/n-InP Schottky contact and 0.80 eV (I-V), 1.12 eV (C-V) and 1.73 for Au/NiPc/n-InP Schottky contact, respectively. Experimental results show that the interfacial layer of NiPc increases the effective barrier height by the influence of the space charge region of the Au/n-InP Schottky junction. Further, Cheung's and modified Norde functions are used to extract the barrier height, series resistance and ideality factors. The discrepancy between barrier heights estimated from I-V to C-V methods is also explained. Moreover, the energy distribution of interface state density is determined from the forward bias I-V data. Results show that the interface states and series resistance play an important role on electrical properties of the structures studied. The reverse leakage current conduction mechanism is investigated. Results reveal that the Schottky conduction mechanism is found to be dominant in the Au/n-InP Schottky contact. However, in the case of Au/NiPc/n-InP Schottky contact, the Schottky conduction mechanism is found to be dominant in the higher bias region, while Poole-Frenkel conduction is found to be dominant in the lower bias region.