Chemical States, Structural, Electrical and Current Phenomenon Properties of a Au/Cobalt Phthalocyanine/Undoped-InP MPS-Type Diode with a CoPc Interlayer

This work reviews the impact of cobalt phthalocyanine (CoPc) interlayers on the electrical and current transport properties of Au/undoped-InP Schottky diodes (SDs). The crystalline quality of CoPc films was confirmed using dominant vibrational bands observed in Raman measurements. Using X-ray photoemission spectroscopy (XPS), the chemical properties were assessed and the results confirmed that the CoPc interfacial layer was deposited on undoped-InP (un-InP). The Au/CoPc/un-InP metal/polymer/semiconductor (MPS) diode showed a better rectification ratio than did the SD. The estimated barrier height (Φ_B) of the MPS diode (0.77 eV (I-V)) was greater than the SD (0.66 eV (I-V)), signifying that Φ_B was modified by a CoPc layer. Using Cheung’s, and Norde methods and Ψ_s-V plots, the Φ_B, ideality factor and series resistance were assessed. The Φ_B values estimated by these techniques were well matched with one another demonstrating their constancy and validity. A lower density of states (N_SS) is attained for the MPS diode than for the SD, demonstrating that the CoPc layer reduced the N_SS. The forward log I-log V plot of both the SD and MPS suggests ohmic-type behavior and space charge limited current (SCLC) in the lower-bias and upper-bias regions. The Poole–Frenkel emission (PFE) is ruled at the lower-bias, while, the Schottky emission (SE) is governed in the upper-bias regions under reverse bias in both the SD and MPS diodes. The findings confirmed that the CoPc layer is a probable material for the construction of organic–inorganic devices.