Fabrication and characterization of polyaniline/Si heterojunction photodetector prepared by laser ablation in liquid

Recently, polyaniline (PANI) has attracted considerable attention for use in photovoltaic applications. In this study, PANI colloidal nanoparticles were synthesized through laser ablation in liquid. The nanoparticles' structural, morphological, and optical properties were analyzed using SEM, X-ray diffraction (XRD), and UV-Vis optical absorption techniques. The XRD results reveal that the PANI nanoparticles are semi-crystalline and highly oriented along the (121) plane. The SEM shows the formation of platelet morphology with the presence of some nanoparticles with average size of 40 nm. The optical properties studies show that the PANI nanostructure has an optical energy gap of 3.75 eV. The fabricated PANI/Si heterojunction photodetector exhibits high-performance; the current-voltage characteristics of PANI/Si heterojunction exhibit rectifying properties and the ideality factor as 3.4. The photodetector exhibited its highest response at 610 nm, achieving a responsivity of 0.58 A/W. The photosensitivity of the photodetector was found ton 80 at bias voltage of 8.5 V and light intensity of 9.7 mW/cm2. The values of the external quantum efficiency EQE and detectivity D* of the PANI/Si photodetector were 2.9 x 1011 Jones and 1.17 x 102%, respectively at 610 nm.