Structural, chemical, optical, electrical and photodiode properties of Au/ ZnPc/undoped-InP MPS-type diode using a ZnPc interlayer

This work explores the effect of zinc phthalocyanine (ZnPc) on the electrical properties of Au/un-InP metal/ semiconductor (MS) diode and characterizes its surface topography, structural, chemical and optical properties using AFM, FESEM, XRD, XPS and UV-Vis procedures. XRD and XPS results show that the ZnPc layer was formed onto the InP substrate. The electrical properties of the Au/ZnPc/un-InP metal/polymer/semiconductor (MPS) diode were measured using the current-voltage (I-V) procedure. The results of MPS were compared with the results of the MS. The MPS diode exhibited a higher rectifying nature with reduced reverse leakage current as compared to the MS. Higher barrier height (Phi b) was obtained for the MPS (0.80 eV) than the MS (0.65 eV). The Phi b, n and RS values of the MS and MPS were evaluated using Cheung's and Norde methods. The Phi b values obtained from the J-V, Cheung's and Norde functions were nearly matched with each other, suggesting their consistency and validity. The lower NSS value was acquired for the MPS compared to the MS, indicating a substantial influence of the ZnPc interlayer on the NSS of the MS diode. The photodiode properties of the MPS structure were also measured under dark and illumination wavelengths ranging from 400 nm to 1000 nm. The responsivity and photo-dark-current ratio properties of the ZnPc/InP photodiode indicate the efficacy of the ZnPc layer as an active photo absorber. The findings suggest that the ZnPc layer has potential material for developing next-generation optoelectronic devices.